Ghost 15 unable to create files on Network drive

I'm running Ghost 15.0 under XP SP3. I have a Network Attatched Storage mapped as my Z: drive. Other applications can read & write to this drive with no problem. But Norton Ghost always comes up with a Delayed Write Failure. This is a fresh install of the OS and Norton and I still can't create backups. Details of the error message from Norton are:

 

--Unable to write to file.

---Error EBAB03F1: The specified network name is no longer available.

---Unable to set file size.

----Error EBAB03F1: An unexpected network error occurred.

(UMI:V-0-2001-31)