backup problem med HP DAT tape

Jeg for fejlmelding hver gang jeg forsøger at tage en backup på vores windows 2003 server som giver følgende fejlmedelelse:
Backup Status
Operation: Backup
Active backup destination: 4mm DDS
Media name: "Media created 15-09-2004 at 19:29"

Backup (via shadow copy) of "E: Brugerdata"
Backup set #1 on media #1
Backup description: "Set created 15-09-2004 at 19:29"
Media name: "Media created 15-09-2004 at 19:29"

Backup Type: Normal

Backup started on 15-09-2004 at 19:31.

Error: The device reported an error on a request to write data to media.
Error reported: Invalid command.
There may be a hardware or media problem.
Please check the system event log for relevant failures.
The operation was ended.
Backup completed on 15-09-2004 at 19:33.
Directories: 109
Files: 1233
Bytes: 44.631.439
Time:  1 minute and  18 seconds

Error: E: is not a valid drive, or you do not have access.
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The operation did not successfully complete.
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Backup Status
Operation: Backup
Active backup destination: 4mm DDS
Media name: "Media created 15-09-2004 at 19:39"

Backup (via shadow copy) of "E: Brugerdata"
Backup set #1 on media #1
Backup description: "Set created 15-09-2004 at 19:39"
Media name: "Media created 15-09-2004 at 19:39"

Backup Type: Normal

Backup started on 15-09-2004 at 19:40.

Error: The device reported an error on a request to write data to media.
Error reported: Invalid command.
There may be a hardware or media problem.
Please check the system event log for relevant failures.
The operation was ended.
Backup completed on 15-09-2004 at 19:42.
Directories: 109
Files: 1233
Bytes: 44.631.439
Time:  1 minute and  9 seconds

Error: E: is not a valid drive, or you do not have access.
----------------------
The operation did not successfully complete.
----------------------
Backup Status
Operation: Backup
Active backup destination: 4mm DDS
Media name: "Media created 15-09-2004 at 19:47"

Backup (via shadow copy) of "E: Brugerdata"
Backup set #1 on media #1
Backup description: "Set created 15-09-2004 at 19:47"
Media name: "Media created 15-09-2004 at 19:47"

Backup Type: Normal

Backup started on 15-09-2004 at 19:50.

Error: The device reported an error on a request to write data to media.
Error reported: Invalid command.
There may be a hardware or media problem.
Please check the system event log for relevant failures.
The operation was ended.
Backup completed on 15-09-2004 at 19:51.
Directories: 109
Files: 1233
Bytes: 44.631.439
Time:  1 minute and  9 seconds

Error: E: is not a valid drive, or you do not have access.
----------------------
The operation did not successfully complete.
----------------------
Der er både blevet skiftet dat drev og tape unden bedre resultat.
Er der nogen som kan hjælpe