I know this has nothing to do with SQL Server, but I wanted to put it out ther and hope it helps someone, somewhere.
If you are like me and you disabled the UAC prompts when you installed Vista, and then you try to add a network printer (in my case the printer was connected to an XP desktop) you get a “Print Monitor Unknown” error. The way to get around this is to re-enable the UAC, then you will get a prompt for the drivers, and then they install. Viola!
Hope this helps!