If you try to connect to a printer that is shared on an SBS 2008 server from a client computer running a 32 bit version of Windows, you may see the following warning message:

This error will appear if the server doesn’t have a 32 bit print driver installed. To eliminate the warning message we need to install the 32 bit print driver on the server. In the following steps, we will discuss one method for adding the 32 bit print drivers to the SBS 2008 server.

From a Windows XP client:

1. Logon to a 32 bit XP client with an account that has Administrator rights on the server.
2. Browse to the server and double click on the Printers and Faxes share. Then Click File and then Server Properties.
3. Go to the Drivers tab. Click Add. The Add Printer Driver wizard should appear. Click Next on the welcome screen.
4. If the client already has a driver for the printer you can select the driver from the list otherwise you would Click Have Disk and browse to the directory containing the print drivers from the printer manufacturer. Once you select the printer you will be prompted to select the print environment. Check the box for Intel Windows 2000 or XP.
5. Click to Finish to complete the process and close the wizard. 

More info: Vista Client