extofer -2 Posting Whiz in Training

I'm having trouble configuring a VPN. I have the router and IP configurations working fine, only problem is that AFTER I connect to the VPN, the network at the VPN Host location goes down. They lose internet connection and some malfunctions within the LAN as well. Am I configuring wrong... how should I do it, aslo, should I have the HOST PC with two NICs???