David,

I found it this morning.
The problem was a field in a grid.
I changed the field type from memo to character in the free table and at the same time changed the field name.
I neglected to change the field name of the control source in the grid.
It would have been helpful if VFP5 would have displayed a proper error message instead of a W98 Invalid Page Fault.

>Allan,
>
>Have you made sure to check the return values of all the TableUpdates() to make sure they are committing the changes? Are you positive you are committing the changes on all tables? Have you stepped through the code in the debugger to find the exact line that's causing the error?
>
>>I have a free VFP5 table that is in the data environment as exclusive and buffer override as '5' (optimistic table buffering). There are several tableupdate(1,.t.) commands in the 'close' form command button of which one is for this free table.
>>When I click on the 'close' command button a Windows 98 'This program has performed an illegal operation. VFP caused an invalid page fault in module VFP.EXE at 018F:0051E7A7' is displayed.
>>I have deleted the free table and recreated it as well as removing the table from the data environment and adding it back in.
>>The problem is related to the buffer mode because when I change it to none, the Windows Exception does not appear.
>>Thank you in advance.