W2K03 R2 server SP2 backup and volume shadow copy errors

Received the following error while attempting to run a backup of my server.
volume shadow copy creation: attempt 1.
timeout before function completed

error returned while creating the volume shadow copy: 0xffffffff

am unable to deselect vol shad cpy and dont wish to use this feature,

how can i perform a backup of my server
without this error

Tks in advance

KoR