Petals Ant Tasks

java.lang.NullPointerException
	at org.ow2.petals.ant.task.monit.AbstractMonitAntTask.execute(AbstractMonitAntTask.java:52)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
	at sun.reflect.GeneratedMethodAccessor57.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.Target.execute(Target.java:435)
	at org.apache.tools.ant.Target.performTasks(Target.java:456)
	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
	at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
	at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
	at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:441)
	... 37 more
Caused by: java.lang.NullPointerException
	at org.ow2.petals.ant.task.monit.BuildFlowTreesTask.processFlowStep(BuildFlowTreesTask.java:136)
	at org.ow2.petals.ant.task.monit.BuildFlowTreesTask.processFlow(BuildFlowTreesTask.java:109)
	at org.ow2.petals.ant.task.monit.BuildFlowTreesTask.doTaskWithFlows(BuildFlowTreesTask.java:68)
	at org.ow2.petals.ant.task.monit.AbstractMonitFlowsAntTaskRequiringRefId.doTaskRequiringRefId(AbstractMonitFlowsAntTaskRequiringRefId.java:39)
	at org.ow2.petals.ant.task.monit.AbstractMonitAntTaskRequiringRefId.doTask(AbstractMonitAntTaskRequiringRefId.java:54)
	at org.ow2.petals.ant.task.monit.AbstractMonitAntTask.execute(AbstractMonitAntTask.java:46)
	... 49 more