Not true. At least the RR service is not incompatible. Running RR here on both Win2000 and XP machines.
http://support.microsoft.com/support/kb/articles/q310/9/94.asp?ID=310994
I spoke directly to RR tech support and they confirmed that they do not support XP. "Some of our customers are running XP with no problems; however others have reported problems. We are in beta right now. XP will not be formally supported by RR until 11/30/01."
--Boris