VPN via Nortel Contivity not working with Dell 2300 Router

I've seen other people with this problem on other message boards, but no one seems to have found a solution.  When I connect to my company's VPN via Nortel's Contivity Client and the Dell 2300 Router, I get hung up on "Checking for banner text" and then it times out saying that the connection was lost.  When I connect straight to the modem, I don't have that problem, which leads me to believe it's an issue with the router.  Has anyone experienced this?  Hopefully with a solution?  Thanks for any input!