Are hidden folders from a NAS device supported for NDMP backups?

Hi,

NAS - EMC VNX5300.
CS - DP 7.03 IB 108 on Win2008R2 standalone server.

Backups of a lot of filesystems are running fine there. However we get a failure with we try to backup a "hidden" FS similar to this one -- /root_xxx/.etc. 
Other folders inside same /root_xxx can be backed up fine so I'm assuming this has something to do with the fact that the folder is hidden.

Error we get is "SnapSure file system creation fails". I tried looking for info in the support matrix and the NDMP integration guide but couldn't find anything. 

Thanks for any reply!