>I forgot to mention that the O/S is WinXP Professional.

I've no problem building FPD 2.6a projects into APP's under WinXPSP1 or Win2K. Maybe one of projects components, like screen or menu, is corrupted? Also, make sure that _GENSCRN and _GENMENU system variables reference proper programs. You can try to delete foxuser.dbf as well.