PNRP resolver-based applications running on XPSP2 with the P2P networking pack installed are running  v1 of the PNRP protocol. It is advisable to upgrade to PNRP v2 which can be downloaded as an XP update from http://support.microsoft.com/default.aspx/kb/920342

Significance for Peer channel applications:

- The main advantage of this upgrade is that your apps are interoperable between Windows Vista and XPSP2

-Shalini.