Question : Problem: Access denied, System error 5 Occured

Dear friends,
I Have a problem accessing to a shared folder on a server from a remote computer thru VPN.
The problem is that when we try to use "net use x: \\BlahBLahBlah\Shared" on the remote computer it returns the "System error 5 has occurred. Access is denied." error, and I am pretty sure that is not a permission problem , and since it connects thru VPN and there is no Problem with its VPN connection it is not a Firewall problem. Any Suggstion??

Answer : Problem: Access denied, System error 5 Occured

I found out that the problem is only when we connect with wireless router, when I connect to internet thru the Cable-Modem it works fine, but when trying to connect using WiFi it is not working, the funny thing is that it connects the VPN correctly and it can see the server but when we want to access it, that stupid error shows up. it is kinda weird, any one has any idea?