StringIndexOutOfBoundsException during move of an issue from "In Progress" to "Done"

If I move an issue from "In Progress" to "Done", i get a "String index out of range: 1 Failed to create Issue." message in the window and an exception in the logfile.

our server runs on:
Jira Enterprise Edition, Version: 3.11-#288
Greenhopper (ENTERPRISE, Version: 3.1-jira310)

the exception is:

java.lang.StringIndexOutOfBoundsException: String index out of range: 1
at java.lang.String.substring(String.java:1935)
at com.pyxis.greenhopper.jira.util.IssueManager.getMethodName(IssueManager.java:346)
at com.pyxis.greenhopper.jira.util.IssueManager.getArgs(IssueManager.java:85)
at com.pyxis.greenhopper.jira.actions.TaskBoardAction.updateIssueState(TaskBoardAction.java:442)
at com.pyxis.greenhopper.jira.actions.TaskBoardAction.doUpdateStatusWithInputs(TaskBoardAction.java:159)
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:597)
at webwork.util.InjectionUtils$DefaultInjectionImpl.invoke(InjectionUtils.java:61)
at webwork.util.InjectionUtils.invoke(InjectionUtils.java:52)
at webwork.action.ActionSupport.invokeCommand(ActionSupport.java:417)
at webwork.action.ActionSupport.execute(ActionSupport.java:146)
at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:54)
at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:132)
at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.service(JiraServletDispatcher.java:209)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.jira.web.filters.AccessLogFilter.doFilter(AccessLogFilter.java:73)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
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:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:182)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.seraph.filter.LoginFilter.doFilter(LoginFilter.java:181)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:132)
at com.atlassian.jira.web.filters.JIRAProfilingFilter.doFilter(JIRAProfilingFilter.java:16)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.jira.web.filters.ActionCleanupDelayFilter.doFilter(ActionCleanupDelayFilter.java:43)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.jira.web.filters.RequestCleanupFilter.doFilter(RequestCleanupFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:72)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:350)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:89)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.core.filters.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:37)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.atlassian.jira.appconsistency.db.DatabaseCompatibilityEnforcerFilter.doFilter(DatabaseCompatibilityEnforcerFilter.java:39)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:541)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:619)