VPN Client

I am trying to connect to one of our customers through Cisco VPN client 4.6.00.0045. When I try to connect through our DSL connection I get thr following error “reason 412 the remote peer is no longer responding”. However if I modify the profile to connect to the internet via dial up I can login and connect. My dial up ISP is not the same company that provides my DSL. I’m new at VPN connections any ideas as to what the problem is?
Thanks