jbpm-console human task display error

[artist123]

Hi,

I created a simp,e hello process and ftl forms to start and stop (sample got from krisv demo in documentation). but task not displayed but it throug the following error...any help......jbpm5.3

2012-08-15 15:42:13,538 [DEBUG] ToolID: Process_Overview.0 2012-08-15 15:42:17,268 [DEBUG] ToolID: Personal_Tasks.2 2012-08-15 15:42:24,448 [DEBUG] ToolID: Personal_Tasks.2 2012-08-15 15:43:21,145 [DEBUG] ToolID: Personal_Tasks.2 2012-08-15 15:44:18,658 [DEBUG] ToolID: Personal_Tasks.2 2012-08-15 15:44:20,048 [DEBUG] GET: 2012-08-15 15:44:20,098 [DEBUG] parse {"tasks":[{"id":1,"processInstanceId":"6","processId":"Hello","assignee":"krisv","isBlocking":false,"isSignalling":false,"outcomes":[],"currentState":"ASSIGNED","participantUsers":[],"participantGroups":[],"url":"/render","priority":0}]} 2012-08-15 15:44:20,099 [DEBUG] parse {"id":1, "processInstanceId":"6", "processId":"Hello", "assignee":"krisv", "isBlocking":false, "isSignalling":false, "outcomes":[], "currentState":"ASSIGNED", "participantUsers":[], "participantGroups":[], "url":" "priority":0} 2012-08-15 15:44:20,106 [FATAL] Uncaught Exception: com.google.gwt.core.client.JavaScriptException: (TypeError): 'value_0' is null or not an object number: -2146823281 description: 'value_0' is null or not an object      at Unknown.$fillInStackTrace_1(JsArrayString.java:42)     at Unknown.$JavaScriptException(StackTraceCreator.java:366)     at Unknown.caught_0(Exceptions.java:29)     at Unknown.$asString(JSONWalk.java:126)     at Unknown.parseTaskReference(JSONWalk.java:48)     at Unknown.parseTaskReferenceList(DTOParser.java:51)     at Unknown.handleSuccessfulResponse_15(LoadTasksAction.java:74)     at Unknown.onResponseReceived_5(AbstractRESTAction.java:78)     at Unknown.$fireOnResponseReceived(Request.java:287)     at Unknown.onReadyStateChange_0(RequestBuilder.java:393)     at Unknown.anonymous(XMLHttpRequest.java:258)     at Unknown.entry0(Impl.java:146)     at Unknown.anonymous(Impl.java:56)