Hi John, can you RDP to the client computer by using the internal network? What's the error message did you receive? Can you connect to other clients othen than the Windows XP client?
You can first take a look at the following troubleshoot KB article:
Remote Desktop disconnected or can’t connect to remote computer or to Remote Desktop server (Terminal Server) that is running Windows Server 2008 R2
http://support.microsoft.com/kb/2477176
Sean Zhu
TechNet Community Support
