System.InvalidOperationException: Failed to map the path...

I am trying to set up some web pages. They are very simple, just listing out files in different directories and linking to them.

The directories are on another server on the network. There is a virtual directory called "F-Drive" on our main network server set up for this purpose

My problem arose when I tried to do a server.mapPath to bind the links to a gridview and I received the error mentioned above -  "Failed to map the path..."

This is the line it bombed out on:
Dim dirInfo As New System.IO.DirectoryInfo(Server.MapPath("/F-Drive/Departments/Test/Shares/Docs/TestDocs"))

I don't know if it's a permissions issue or a web.config setting.

I would appreciate any help wtih this.