>Since I'm doing a lookup in a very small table (10 records) that isn't updated, I very much doubt the index be corrupt. My best guess is that something is 'wrong' with the table in the current workarea. If I open the debugger, I will get the error only once. The second the seek command works. Maybe a problem in VFP5?

Yes, I believe so - see my other response, I think there was a bug, though I don't see it in MSDN now, I vaguely recall it.