Windows 7 cannot access to a server

Hello everybody,

We have 5000 workstations with both Windows 7 (4000 workstations) and  windows XP (1000 workstations left).We access to a directory on a file server using a  Windows XP workstation  but when we are trying to access to the same file server with Windows 7;we have the message "Winodws cannot acces to "the name of the server" ";This happend just to our windows 7 workstations..

I need help to what i cannot access to this server.

Thank you.

Regards,

Le Balbo