VPN Issues

My company uses a VPN for our remote users. As far as I can tell we have it configured properly but there is one nagging problem. That problem is that a user can connect to the VPN from home and access all network resources (file servers, etc) However, if the user disconnects from the VPN and then reconnects without rebooting, they will be unable to access any network resources. The error that is received is “An error occured while reconnecting . Microsoft Windows network. The local device name is already in use. The connection has not been restored.” I am at a complete loss as to the cause of this problem and it has become quite annoying. If anyone has any experience with type of situation I would appreciate you help. I am not sure what further info to provide so if you need more inforation please ask and I will do my best to provide it. Thanks