we are updating in our sistem from jbpm 4.3 to 4.4 and we have a problem with timeout timer in subprocess

this code is working in jbpm 4.3 :

       <sub-process  name="prc1" sub-process-key="prc1">
                    <parameter-in subvar="pc" var="pc"/>
                    <parameter-out subvar="pc" var="pc"/>
                    <transition  name="timeout" to="prcTimedOut">
                              <timer duedate="#{dueTimeInSeconds}"/>
                    </transition>
                    <transition  name="end" to="markProcessAsEnded"/>
          </sub-process>
  
          <java continue="async" expr="#{prcProcessor}"  method="prcTimeout" name="prcTimedOut">
                    <arg><object expr="#{pc}"/></arg>
                    <transition to="markProcessAsEnded"/>
          </java>

in jbpm 4.4 we get exception when timer fires :

[16/04/13 18:39:03:003] [pool-11-thread-1] ERROR org.jbpm.pvm.internal.cmd.ExecuteJobCmd: exception while executing 'timer[140008|2013-04-16 18:38:57|timeout]'
org.jbpm.api.JbpmException: execution[prcMain.9JPOVJXl7JQQTnSvyZWJzQAAAAAAAAAAAAAAAAAAAAA=.prc1.140007] has running subprocess: execution[prc1.140009] in state active-root
          at org.jbpm.pvm.internal.model.ExecutionImpl.checkActive(ExecutionImpl.java:1086)
          at org.jbpm.pvm.internal.model.ExecutionImpl.signal(ExecutionImpl.java:424)
          at org.jbpm.pvm.internal.model.ExecutionImpl.signal(ExecutionImpl.java:416)
          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 org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:157)
          at org.jbpm.pvm.internal.model.ExecutionImpl$$EnhancerByCGLIB$$80e585a7.signal(<generated>)
          at org.jbpm.pvm.internal.job.TimerImpl.execute(TimerImpl.java:92)
          at org.jbpm.pvm.internal.job.TimerImpl.execute(TimerImpl.java:50)
          at org.jbpm.pvm.internal.cmd.ExecuteJobCmd.execute(ExecuteJobCmd.java:79)
          at org.jbpm.pvm.internal.cmd.ExecuteJobCmd.execute(ExecuteJobCmd.java:41)
          at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)
          at org.jbpm.pvm.internal.tx.SpringCommandCallback.doInTransaction(SpringCommandCallback.java:45)
          at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:128)
          at org.jbpm.pvm.internal.tx.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:49)
          at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.executeInNewEnvironment(EnvironmentInterceptor.java:53)
          at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:40)
          at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:56)
          at org.jbpm.pvm.internal.jobexecutor.JobParcel.run(JobParcel.java:48)
          at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
          at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
          at java.util.concurrent.FutureTask.run(FutureTask.java:138)
          at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
          at java.lang.Thread.run(Thread.java:662)

can someone point me to a good documentation , because in developer guide I dit not found info  i need

Thanks !