VPN CONNECTIONS

We have been using pcanywhere thru a vpn connection from one remote site to our main site for awhile without any problems. in the last few weeks we have been disconnected thru our pcanywhere software but the vpn connection stays connected. we are also noicing that our other connections such as Terminal servers is also disconnecting and any net shares. we are using ISA servers to connect vpn and windows 2000 as o/s.