Hi,
Do the workstations have a scheduled virus scan which causes the problem. What do the server & the workstation event logs show.
Check for scheduled tasks in the event scheduler, maybe someone is downloading something after hours, see what processes are running on each of the workstations.
Also if these workstations are on a separate network segment what is the bandwidth utilization which is causing a network timeout.

>Hi,
>
>Some of our customers are experiencing something quite strange.
>They are using our app (local exe's) which uses databases on a central server 2003.
>
>Starting from a certain hour in the early evening (some 18u, others a bit later) they start getting Error reading file-errors.
>
>We already checked if there's any backup-program starting or something else, but no, not a thing.
>
>Does anyone have an idea what could be causing this? Maybe some obscure setting in Server 2003 ?
>
>Thanks for any hints.
>
>Guillaume