In a Windows AD environment, where the Full Qualified Domain Name (FQDN) and the NetBIOS (Pre-windows 2000) domain name does not match, Filr users are unable to access the Net Folders created for SharePoint.
A "Unauthorized access" error is seen in the appserver.log for the users trying to access these SharePoint Net folders.
A fix for this issue is part of Filr 3.4.2 and later, available over the update channels.
In this particular situation, Filr authenticated the users to SharePoint using a wrong NetBIOS name for the domain.
An example of such a setup would be:
The domains FQDN: DA.digitalairlines.com
The NetBIOS (Pre-windows2000) domain name: DIGITALAIRLINES.