javax.portlet.PortletException and java.lang.StackOverflowError

I am seeing the following error while navigating to Folders > System > Login Page Rules > My webMethods Login Rule. Seeing coming up almost in every rule. under Folders >System.

[POP.001.0002] A “javax.portlet.PortletException” occurred with the
Message “javax.faces.el.EvaluationException: Error getting property
‘varInfosProvider’ from bean of type
com.webmethods.portlet.ruleviewer.RuleViewerViewPage:
javax.faces.el.EvaluationException: javax.faces.el.EvaluationException:
Error getting property ‘ruleVarInfos’ from bean of type
com.webmethods.portlet.RuleEditingBean: java.lang.StackOverflowError”

Detail error:

 java.lang.StackOverflowError
        at java.lang.ref.Reference.<init>(Reference.java:301)
        at java.lang.ref.FinalReference.<init>(FinalReference.java:16)
        at java.lang.ref.Finalizer.<init>(Finalizer.java:161)
        at java.lang.ref.Finalizer.register(Finalizer.java:193)
        at
sun.reflect.GeneratedConstructorAccessor47.newInstance(Unknown Source)
        at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingCons
tructorAccessorImpl.java:27)
        at
java.lang.reflect.Constructor.newInstance(Constructor.java:494)
        at java.lang.Class.newInstance0(Class.java:354)
.....

Anybody knows why this error popping up and resolution.

Thanks.