Signaling and waiting on Event

Hi there,

Is there somthing wrong in a Dispatch level routine signalling a non paged
pool Event while
a Passive level thread is doing a KeWaitForSingleObject() on that event at
the same time .
I sometimes get a bugcheck with IRQL_NOT_LESS_OR_EQUAL in such a scenario
?
The event was initialized to Non signaled state before the scenario .

thanks,
Dubi