VPN connection issues

I can connect through the Microsoft VPN that comes with XP to my work computer.  However it will not connect to my wife's work computer.  It gives me "error 800". 

I have previously used the Cisco VPN, but can not load it on the XP Media Ctr 2005.

 

Any suggestions on why it works one way but not the other?  (I can connect to wife's work through Cisco VPN on my laptop from home, so I know its not an issue with that server being down)