File Sharing / Network Resources

We have a Windows 2008 server acting as a read only domain controller  and file sharing server at a branch office. When the office loses their Internet connection, users can no longer access the shares on this server. As soon as the Internet connection is back, the resources are once again available. No error message is provided at all. It simply creates a blank white window and never populates with anything. Any ideas would be greatly appreciated!

Their shortcuts to these shares are setup as \\IP Address\Share so it is not a DNS issue.

Thank you