Craig,

Thanks for your suggestion:
I blew the indexes away and recreated them. I tried using the table with NO indexes. I tried using a different field in the WHERE clause. I tried using NO WHERE clause. I've tried a simplified UPDATE expression. I have the proc return the SQL string to the calling browser window and it appears to be correct and intact. I tried compiling as a Single DLL instead of a MTDLL.
I am now getting NO UPDATE action at all.
HOWEVER:
If I call the proc from the VFP command window using CreateObject it behaves correctly. If I call it from a browser/asp page, it doesn't. I've tested the variables being passed and they all appear correct when they arrive at the proc.

David