>I am running a 16C6x/7x probe (16J) on PicMaster under MPLab.  The code
>runs fine, but when it is stopped, I get a Stack underflow or overflow
>message box.  The message box reappears annoyingly often when I single
>step.    <snip>

Todd - I had the same problem with my last project (16J probe).  I am using
an external watchdog timer / POR and that turned out to be the problem.
Whenever I halted the processor, the watchdog would continually reset the
pod.  I lifted the output pin of the watchdog and the problem went away.

Dwayne