>>- Can you confirm that what you're trying to INSERT doesn't contain anything nasty like CHR( 0 )?
>
>So, found CHR(0) in the data I'm saving, but eliminating it isn't fixing the problem. I was so sure that was it.

Chr(0) rings a bell from vfp6 times we never really solved, but coded around: With active transactions vfp inserted chr(0) even when data was correct/without them. Was the error table written to openend shared or excl ?

More from the previous line of thought of Windows messing up shares/drive letters/buffers:
Try a tap dance of
closing/reopening/inserting ***static*** record + datetime()/closing/reopening
the table again in case it currently is already open from previous calls when you insert.

HTH
thomas