System state NT backup issue

Hi,

The following error comes for me when I execute NTBACKUP in my windows server 2003

Backup Status
Operation: Backup
Active backup destination: File
Media name: "backup.bkf created 12/26/2013 at 1:42 PM"
 
Volume shadow copy creation: Attempt 1.
 
Error returned while creating the volume shadow copy:0x8004231f.
 
Error returned while creating the volume shadow copy:8004231f
Aborting Backup.
 
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The operation did not successfully complete.
 
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Any help to solve this issue is greatly appreciated!

Thanks,

Sivakumar