What OS is being used for the server?

>A single copy of our application resides on the 'Server' of a Peer to Peer network. The application works flawlessly when run from the 'Server' on which the .exe resides. However when we execute the application from a workstation it fails. The same application works just fine when run from a workstation when installed on a server based network.
>
>The statement that fails is :
>
> IF FILE(data\filename)
> ...
> ENDIF
>
>The file definitely exists but the program behaves as though it does not exist. Why can't a workstation on a peer to peer network find this file on the shared drive?
>
>Thanks in advance.