Backup to tape fails ID 3311 & 2033

Hello,
I am trying to implement tape backup with my primary DPM Server using 
firestreamer and removable media.  I protect 11 servers with my primary DPM 
server successfully.  I also protect the primary DPM with a Secondary DPM 
successfully.  From the PrimaryDPM I can backup to tape from disk replica 
successfully on 10 of the 11 protected servers.  Everytime I get to my Nas2 
Server [an Iomega Nas running Server 2003 Appliance edition] I get the 
following error...

DPM encountered an error while performing an operation for 
\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1610\a9b6dbc7-66d4-4043-bf17-a2bdc
df085b6\Full\A-Marketing 
and Business Development\Images\PROJECTS\CLOSED PROJECTS\Community Banks of 
Northern CA\2007_06\6_13\pic4updated.jpg (ID 2033 Details: The device is not 
ready (0x80070015))

It happens on a different file everytime and at different times through the 
backup.  I have disabled protection, mounted the nas2 replica volume, and run 
Chkdsk /F on it. Then dismounted, reenabled protection and retried the tape 
backup manually.  But the job always fails with the same error on a different 
file everytime.

Does anyone have any ideas?

Thanks