ntbackup error in windwos 2003 server

Backup Status
Operation: Backup
Active backup destination: File
Media name: “Backup.bkf created 02/12/2006 at 1:24 PM”

Volume shadow copy creation: Attempt 1.
Timeout before function completed

Error returned while creating the volume shadow copy:0xffffffff.

Error returned while creating the volume shadow copy:ffffffff
Aborting Backup.

———————-

The operation did not successfully complete.