Welcome to the Fox Land, where not quite often normal things happens !!!

Ok, that maybe sound basic, but:

1- You use TCP-IP?? NetBios?? Two Mixed???. TCP-IP is best, so quit any other communication protocol (i heard that somethings with multiple protocols some data is send in one and the other data is send in the other...)

2- How many records you manipule? This is caused in any table, or only in a specfic table???

3- Rebuild the table... I get strange things with a table when null-rare chars come... The ONLY workaround is build a complety new table and re-insert the data. Not work if you run a table-fix utility in some cases

4- Are you try explicit insert??? that is, INSERT INTO (Any) VALUES(DefaultValue)

5- You use pessimist, optimist, row or table locking??? Is more safe turn optimistc-row locking...

6- WHY YOU DON'T HAVE A Client/Server design!!!! If this cause troubles so long time ago, maybe is time to go away file-acces and turn it in a n-tier layer... With the time spend in looking a answer maybe you can re-write the whole app...

7- Relate to 6: Is posible try if send sql commands to a COM server hiting the table not cause this??? Is possible fetch small dataset?? That its, only get one record at-time.

Something about the file-handling error say me that exist a problem with large data (a protocol issue???)

8- NOT DELETE!!! Put a logic delete, that it, add a field called "Hey man delete it!!!" and build a utility to do a real delete (in the server and use DELETE FROM) running, for example, only a time each day.

9- The tables come from FPW and simply use it??? Rebuild all tables in VFP...

10- Exist codepages conflict!!! Turn all client/serves to the same codepages... for example go to control page and set the same languaje. I have troubles with Sql DataEngine ONLY because a have language set to SPANISH-Colombia...

11- if use a string key, you can replace it for a integer key????

No more ideas from now....I hope that you can resolve this starnge trouble and can sleep happy again!!!