>>Are you running on Terminal Services, or just a regular client?
>
>Thank you all for the suggestions.
>This error is really rare, happens every 6 months only.
>
>The application is running on regular clients, using a mapped drive to acces the server,
>using native tables.
>
>Any other suggestion ?

Not from here at the moment. Al's suggestions for network troubleshooting are probably the most useful.