Error editing custom issue type

Apologies, I'm unable to reproduce this...
Created a custom issue type, but used a 'http://blah' url, and wished to change it.

A restart of orion appears to have fixed it, but trying to delete the issue before complained about there being no such issue type with that id (even though it was checking the correct id), and clicking Edit before restarting orion gave:

2003-12-10 12:59:43,107 [ApplicationServerThread] ERROR webwork.dispatcher.ServletDispatcher - Could not execute action
java.lang.NullPointerException
at com.atlassian.jira.web.action.admin.constants.AbstractEditConstant.doDefault(AbstractEditConstant.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at com.atlassian.util.profiling.object.ObjectProfiler.profiledInvoke(ObjectProfiler.java:68)
at webwork.action.ActionSupport.invokeCommand(ActionSupport.java:426)
at webwork.action.ActionSupport.execute(ActionSupport.java:146)
at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:46)
at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:131)
at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.service(JiraServletDispatcher.java:361)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:336)
at com.evermind._hb.doFilter(.:59)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:129)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:61)
at com.atlassian.jira.web.filters.SitemeshExcludePathFilter.doFilter(SitemeshExcludePathFilter.java:39)
at com.evermind._ha.doFilter(.:16)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:161)
at com.evermind._ha.doFilter(.:20)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:181)
at com.evermind._ha.doFilter(.:20)
at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:132)
at com.evermind._ha.doFilter(.:20)
at com.atlassian.jira.web.filters.ActionCleanupDelayFilter.doFilter(ActionCleanupDelayFilter.java:26)
at com.evermind._ha.doFilter(.:20)
at com.atlassian.jira.web.filters.AppConsistencyFilter.doFilter(AppConsistencyFilter.java:92)
at com.evermind._ha.doFilter(.:20)
at com.atlassian.jira.web.filters.EncodingFilter.doFilter(EncodingFilter.java:53)
at com.evermind._cub._pod(.:383)
at com.evermind._cub._bmc(.:177)
at com.evermind._ax._ltc(.:666)
at com.evermind._ax._uab(.:191)
at com.evermind._bf.run(.:62)