NullPointerException in com.cenqua.crucible.actions.create.EditRevisionsAjaxAction

From a customer's log:

15:23:30 ERROR - /json/cru/<repo>/editRevisionsFromRevisionAjax/
java.lang.NullPointerException
at com.cenqua.crucible.actions.create.EditRevisionsAjaxAction.execute(EditRevisionsAjaxAction.java:253)
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 com.opensymphony.xwork.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:358)
at com.opensymphony.xwork.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:218)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:192)
at com.cenqua.crucible.interceptors.ReviewInterceptor.intercept(ReviewInterceptor.java:50)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.cenqua.crucible.interceptors.CruciblePermissionInterceptor.intercept(CruciblePermissionInterceptor.java:40)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.cenqua.crucible.interceptors.HasCrucibleInterceptor.intercept(HasCrucibleInterceptor.java:27)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:186)
at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:116)
at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:273)
at com.opensymphony.webwork.dispatcher.ServletDispatcher.service(ServletDispatcher.java:111)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:502)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1208)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:55)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:41)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1200)
at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:55)
at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:41)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1200)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:83)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1200)
at com.cenqua.crucible.filters.CrucibleFilter.doFilter(CrucibleFilter.java:141)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1200)
at com.cenqua.fisheye.web.filters.TotalityFilter.doFilter(TotalityFilter.java:245)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.mortbay.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1200)
at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)