This error may occur if the library is wrongly configured.
Kindly check your library configuration.
http://seer.entsupport.symantec.com/docs/327396.htm
Tools -> Recipients -> New -> Select Person (or any other option as per your requirement) -> Click OK -> Put your Name in Name filed -> Check the Enable option -> Put your mail address in the address field -> Click OK -> Click yes on the dialog box...
Agree with Ken....
Since TEST.TXT was backed up on Monday's backups it will be restored when you restore the Monday Full, and will still be there after you restore the Tuesday DIfferential
Please hard set the NIC settings as 100mbps of the remote server and try and also find one more thing ..
the tape drive your using if it is compatibile with BE 12.5 or not.