M-Audio has posted a new Windows XP Driver (The Windows 2000 page doesn't list this Driver) for the Revolution 7.1, bringing it up to version 5.10.00.0041. There's no word on the M-Audio website what's changed beyond being WHQL certification, though over on AVS Forums (http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=296249) you'll find some user feedback.
The Driver can be downloaded directly here (http://www.midiman.net/support/drivers/Revo_1022_web_WHQL.exe).