There are a few ways I've found to diagnose a prefetch abort:
1.)Turn on QS_QK_SCHEDULE filter and put QS::flush() in your exception handler. Qspy will then point you to the offending task.
2.)Put a breakpoint on the exception handler and look at the stack and core registers over many failure repitions in hopes of finding a code address that points you to the offending code.
2009-07-02 18:43:37 UTC in QP State Machine Frameworks