>I check the code ( isn't mine) and I find out that this a very simple app opens the dbc and then the needed tables (no cursors, no views) and at the long on the apps append a record in the logusers table and then is whe it happens, the code is a simple serie of replace statements...

Ensure that:
- the user has enough disk space
- the server has enough disk space
- the user doesn't have the app opened twice
- someone doesn't have an exclusive lock on the table

You might want to get them to reboot their pc.