When your admin installed the printer on a server and shared it, it will share with the same printer driver that was installed. If your computer is a match for that driver in both OS and/or 32 bit or 64bit, it will install automatically. However if you attempt to add that printer with a different OS that requires a different version of the driver, you will get the error message, "The server .... does not have the correct driver installed". You can manually install the correct driver OR your admin can fix the server.
Your admin can fix this by doing the following ON THE SERVER:
Click File - Properties on the printer that is failing
Click on the "Sharing" tab
Click on Additional drivers
Install the drivers for the OS you are using
The next time you go to add this printer, it will figure out you need the vista or x64 driver and install it automatically.