DSL and DNS Problem

[coldfuzion]

I am trying to create a VPN between a home office, with AT&T DSL, to our main office sitting on a DS3.
At the home office i am using a Linksys WRVS4400N Wireless-N Gigabit Security Router with VPN. I am using a Speadstream 5100 DSL Modem.
The problem is with the home office and the Linksys. As soon as I put in the VPN info and save it, I loose DNS. Just putting the settings in, not even attempting to connect causes this. As soon as I remove the VPN settings i get DNS back. I have put in the static DNS from AT&T into the Linksys, but same issue. Does anyone have any ideas on this?
Thanks in advance.