Error in starting a workflow with a z event.

I have implemented an event in an object which gets generated through PA30. But when the event gets generated the workflow does not get triggerred and instead an error msg comes in event trace ie.

"Event EMPLOYEEI CHANGED for task WS90000048 not defined as start/end event"

And the linkage gets deactivated.

Can you please suggest what is the problem and the solution too.