VPN- HELP!!

We currently have 2 servers. For the most part, one authenticates (server2); the other is a file server/Exchange (server1). We have been using VPN (PPTP) for the past year. Server2 authenticates and lets the user on to server1. We had to do someLoad sharing and moved some files on to server2. Here is the strange part. If a remote user is in the office they can see the files on server2; however, if they use VPN they can see the server in Network Neighborhood, but cannot access the server;however server1 is fully available. To make the problem even more strange, is if the user dials directly into the network, they can see server2.

Any ideas?