Found the problem. When I download the control strategy and if there is an illegal function code I toss it and of course bump the DPTR to get the next command. (Stupid lack of error checking) When I simulated the code I typed in the hex code correctly into the buffer which would simulate fine. The problem is the download strategy program was not transmitting a hex value of zero, which to VB must be a null or something. When I examined the micro buffer with the monitor program it was obvious.

Thanks all,

Joe