At this point, all I can think of is that there is some typo in your PARAMETER statement (wrong spelling?). In that case, the error would fire when you tried to pass params, and before it even got to the typo.
Try the same process (passing params) from a VFP client. That might help narrow this down a bit.
The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts. - Bertrand Russell