WinXP VPN problem

I recently acquired satellite DSL and use my laptop to connect to my corporate network via VPN. Before when I had land-line DSL, I could connect to the VPN with no problems, but now when I try it, I get an error message that the server is not responding. I have taken the laptop to other connections to test the VPN and it is working properly except when on my satellite DSL. Suggestions??

Thanks