When requesting issues with RSS view for one custom field value instead of a date I've got an exception. See the excerpt from the xml below. When XML is viewed from the browser, this issue contains a valid date.

<rss version="0.92">
<channel>
<title>JetBrains JIRA</title>
<link>http://www.jetbrains.net/jira</link>
<description>This file is an XML representation of some issues</description>
<language>en</language>
<item>
<title>[IDEADEV-8070] Dependant DOM model support</title>
<link>http://www.jetbrains.net/jira/browse/IDEADEV-8070</link>
<description><p>Some DOM models depend on the other's contents, e.g. Struts or JSF config files may be listed in web.xml. We need to fire DOM events on the depending model after some changes in its dependency.</p></description>
<environment />
<key id="79029">IDEADEV-8070</key>
<summary>Dependant DOM model support</summary>
<type id="2">New Feature</type>
<priority id="5">Normal</priority>
<status id="1">Open</status>
<resolution>Unresolved</resolution>
<assignee username="peter">Peter Gromov</assignee>
<reporter username="peter">Peter Gromov</reporter>
<created>Fri, 4 Aug 2006 16:42:07 +0400 (MSD)</created>
<updated>Fri, 4 Aug 2006 16:42:07 +0400 (MSD)</updated>
<fixVersion>Demetra Next EAP</fixVersion>
<component>J2EE.EJB2</component>
<component>J2EE.EJB3</component>
<votes>0</votes>
<customfields>
<customfield id="customfield_10071" key="com.atlassian.jira.toolkit:comments">
<customfieldname>Number of Comments</customfieldname>
<customfieldvalues>
<customfieldvalue>0.0</customfieldvalue>
</customfieldvalues>
</customfield>
<customfield id="customfield_10073" key="com.atlassian.jira.toolkit:participants">
<customfieldname>Participants</customfieldname>
<customfieldvalues />
</customfield>
<customfield id="customfield_10060" key="com.atlassian.jira.ext.charting:resolutiondate">
<customfieldname>Resolution Date</customfieldname>
<customfieldvalues>An error occurred whilst rendering this message. Please contact the administrators, and inform them of this bug.

Details:
-------
java.lang.NullPointerException
at java.util.Calendar.setTime(Calendar.java:1032)
at java.text.SimpleDateFormat.format(SimpleDateFormat.java:785)
at java.text.SimpleDateFormat.format(SimpleDateFormat.java:778)
at javax.mail.internet.MailDateFormat.format(MailDateFormat.java:134)
at java.text.DateFormat.format(DateFormat.java:314)
at com.atlassian.jira.web.util.OutlookDate.formatRss(OutlookDate.java:109)
at sun.reflect.GeneratedMethodAccessor1263.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:267)
at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:197)
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175)
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:230)
at org.apache.velocity.Template.merge(Template.java:256)
at org.apache.velocity.app.VelocityEngine.mergeTemplate(VelocityEngine.java:450)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:76)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:60)
at com.atlassian.velocity.DefaultVelocityManager.getEncodedBody(DefaultVelocityManager.java:55)
at com.atlassian.jira.plugin.JiraResourcedModuleDescriptor.getHtml(JiraResourcedModuleDescriptor.java:97)
at com.atlassian.jira.plugin.customfield.CustomFieldTypeModuleDescriptor.getViewXML(CustomFieldTypeModuleDescriptor.java:131)
at com.atlassian.jira.web.action.issue.IssueNavigator.getCustomFieldXML(IssueNavigator.java:532)
at sun.reflect.GeneratedMethodAccessor8098.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at webwork.util.InjectionUtils$DefaultInjectionImpl.invoke(InjectionUtils.java:61)
at webwork.util.InjectionUtils.invoke(InjectionUtils.java:52)
at webwork.util.ValueStack.findValue(ValueStack.java:426)
at webwork.util.ValueStack.findValue(ValueStack.java:175)
at webwork.view.taglib.WebWorkBodyTagSupport.findValue(WebWorkBodyTagSupport.java:61)
at webwork.view.taglib.BasicPropertyTag.doStartTag(BasicPropertyTag.java:54)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_property_6(navigator_002drss_jsp.java:506)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_if_2(navigator_002drss_jsp.java:430)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_iterator_1(navigator_002drss_jsp.java:387)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_if_1(navigator_002drss_jsp.java:353)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_property_2(navigator_002drss_jsp.java:319)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_iterator_0(navigator_002drss_jsp.java:281)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspx_meth_webwork_if_0(navigator_002drss_jsp.java:238)
at org.apache.jsp.secure.views.navigator.navigator_002drss_jsp._jspService(navigator_002drss_jsp.java:120)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:704)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:474)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:409)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)
at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.service(JiraServletDispatcher.java:253)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.jira.web.filters.AccessLogFilter.doFilter(AccessLogFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55)
at com.atlassian.jira.web.filters.SitemeshExcludePathFilter.doFilter(SitemeshExcludePathFilter.java:38)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:177)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:132)
at com.atlassian.jira.web.filters.ProfilingAndErrorFilter.doFilter(ProfilingAndErrorFilter.java:25)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.jira.web.filters.ActionCleanupDelayFilter.doFilter(ActionCleanupDelayFilter.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.johnson.filters.JohnsonFilter.doFilter(JohnsonFilter.java:91)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.jira.web.filters.gzip.GzipFilter.doFilter(GzipFilter.java:72)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:298)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.atlassian.core.filters.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:37)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:300)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:374)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:743)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:675)
at org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:866)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:595)</customfieldvalues>
</customfield>
<customfield id="customfield_10011" key="com.atlassian.jira.plugin.system.customfieldtypes:float">
<customfieldname>Fixed in build</customfieldname>
<customfieldvalues>
<customfieldvalue>5595.0</customfieldvalue>
</customfieldvalues>
</customfield>
<customfield id="customfield_10072" key="com.atlassian.jira.toolkit:attachments">
<customfieldname>Number of Attachments</customfieldname>
<customfieldvalues>
<customfieldvalue>0.0</customfieldvalue>
</customfieldvalues>
</customfield>
</customfields>
</item>
</channel>
</rss>