Hi,
On the server console goto Computer Management/Shared Folders/Open Files it will tell you who and what file is open.
It could be that caching is active on the server and the locks are not being released quick enough by the server.
If you can find which file it is it would also help, i.e. put some more error checking code in your app.

>Hi all
>I have an application running in server2008 with terminal services used by 10/15 users.
>Recently I'm getting the error message "File is in use by another user" many times!!! and I can´t figure whats happening. The changes made sinse are not related...
>Is there any way do know ho is using that file, and what's the file?
>Thanks in advance,
>NPedro