Events handling : MWS, CAF

I’m new to CAF. I’ve tried to subscribe for standard event(Login,Login failed etc.) in one of my portlets.
I’ve created an event handler for “Login failed” event type with one action (FireAjaxEvent)defined.
The problem is that can get response from the server side to the portlet using Open Ajax Script control.
I couldn’t find any information in MWS logs that event has been triggered. I’ve got “Events Data Collector” already installed.
Could somebody give me the information how can I diagnose it, are there any tools for diagnosing cases like that.

I’ve also found disturbing thing in MWS handlers section: Folders > System > CAF Event Storage > MyPortlet > handlers ,
there are many entries like: Failed to evaluate binding expression: “#{PortalResultPanelPage.ruleEditingBean.portalRuleDropDownPicker}”

thanks in advance