VPN login problem

I am running a Windows 2000 environment using a SonicWall Soho50 as our firewall and client vpn software. I have two servers which are both domain controllers and dns servers. For some reason the client computer can vpn into one of the servers which is the exchange server but the other one which contains all of our file she cannot. i have tried mapping network drive via name and IP address I can get the vpn connection working properly for a day after an uninstall and a reinstall put once we reboot the client she cannot get into our file server. Any sugegstions? Anything will help at this point.