NPE during MoveSubtask on JAC

2010-08-26 08:35:04,911 http-172.16.3.44-9080-Processor26 ERROR anonymous 515x378047x1 196yton /secure/MoveSubTaskChooseOperation!default.jspa [webwork.dispatcher.ServletDispatcher] Could not execute action
java.lang.NullPointerException
        at com.atlassian.jira.web.action.issue.MoveSubTaskChooseOperation.doDefault(MoveSubTaskChooseOperation.java:51)
        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:70)
        at webwork.util.InjectionUtils.invoke(InjectionUtils.java:56)
        at webwork.action.ActionSupport.invokeCommand(ActionSupport.java:433)
        at webwork.action.ActionSupport.execute(ActionSupport.java:157)
        at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:55)
        at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:139)
        at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.service(JiraServletDispatcher.java:171)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)