strange corruption?

Hi,
I have the following statement in a function.
    UPDATE orderseq    SET orderseq_number = (orderseq_number + 1)    WHERE (orderseq_name='InvcNumber');

All it does is update a single record by incrementing a value (int).

But it never completes.  This has to be some sort of bug.  Anyone have a 
thought what would cause this to occur.  To my knowledge it was working 
and does work in other databases.

Johnf