NIS2009 disabling peer-to-peer network

I upgraded two networked, identical Dell, Windows XP computers to NIS2009.  I've upgraded every year without a problem.  This upgrade caused the machines not to see each other and no network mapping could be reestablished until NIS2009 was removed from both machines.  The 4 hour "chat" with Symantec controlling the machines and shutting off all firewalls did not solve the problem.  Does anyone recognize this problem?

 

Kinder