I see you are trying to be specific, but could you be a little more specific? Particularly with regards to the second part of your question.
If you are saying you can MAP a network drive across the VPN tunnel, but then when someone opens the drive they can’t see any contents, it is possible your link is slow and with the added encapsulation of the encryted wrapper, you may not be giving it enough time for all the contents of the folder to come across the connection.
That is one possibility.
How fast is the circuit?