I can´t no longer access to a shared folder.

Hi,

I´ve got a windows 2003 domain in a central office where i have a shared folder, and a delegation with a computer working as workgroup connected by VPN to the central, i had this shared folder mapped as a network unit but it has stop working and now when i try to access to this network an error message appear saying "this network resource is no longer available".

I have try to connect to this network resource using another credentials (as administrator) but it fails, I can ping from the delegation computer to the central server and connect to it by using terminal server,and I can ping from the central server to the delegation computer I have verified time sincronization among central server and the delegation, I can access to a shared folder in the delegation computer from the central server
(the opposite path). I have disabled the kaspersky firewall installed in the delegation computer and the windows firewall. I also have created a new shared folder in the server without any access permissions but i neither can access to it. I have scanned the delegation computer with several antivirus in order to discard any virus issue.
Does anyone what could be happening?.

Thanks in advance.