SBS2003 Backup using Storagecraft Shadowprotect fails

Hi all,
I have an SBS 2003 Server with two Partitions C & D backing up to a USB Drive each night.

I backup using Storagecrafts Shadowprotect software

C = Operating System
D = Data

D drive backs up every night will out a problem. C Keeps failing to backup though.

Heres the log:

28-Jan-2010 21:00:01 service 100 service (build 43) started job by full trigger
28-Jan-2010 21:00:01 service 300 trial period has 29 days left
28-Jan-2010 21:00:01 service 104 3.5.1.4183 C716-C0CE 7466-684F
28-Jan-2010 21:00:01 service 100 backup volume C:\ (NTFS)
28-Jan-2010 21:00:01 service 100 VDIFF was disabled and then enabled on C:\
28-Jan-2010 21:00:01 service 102 creating snapshots for  

\\?\Volume{138a9260-963f-11dd-bdfb-806e6f6e6963}

\\?\Volume{689b8eff-964d-11dd-a2b4-000cf1e9d3bd}
28-Jan-2010 21:00:01 service 199 try snapshot by  VSS API by STC provider
28-Jan-2010 21:00:01 service 302 Cannot take snapshot. Error: VSS provider bad state.

Method:  VSS API by STC provider. Volumes count: 2.
28-Jan-2010 21:00:01 service 301 try snapshot without writers
28-Jan-2010 21:00:01 service 302 Cannot take snapshot. Error: VSS provider not

started. Method:  VSS API by STC provider. Volumes count: 2.
28-Jan-2010 21:00:01 service 199 try snapshot by  VSNAP API directly
28-Jan-2010 21:00:22 service 150 retrieving snapshot names.
28-Jan-2010 21:00:22 service 103 snapshot was created by  VSNAP API directly. It took

21 seconds
28-Jan-2010 21:00:22 service 104 image will be created by VDIFF
28-Jan-2010 21:00:22 sptask 111 sbrun -mdn ( sbvol -fi \\?\STC_SnapShot_Volume_21_0

\\?\Volume{138a9260-963f-11dd-bdfb-806e6f6e6963} : sbcrypt -53 : sbfile -wd

G:\Backups\C_VOL-b001.spf )
28-Jan-2010 21:00:22 sptask 110 Worker thread has started
28-Jan-2010 21:00:23 (loader) 112 corelogic version: 3.5.225.4241
28-Jan-2010 21:00:23 sbvol 109 free space exclusion on
28-Jan-2010 21:00:23 sbvol 107 incremental tracking is on, generation count: 0
28-Jan-2010 21:00:23 sbvol 117 incremental tracking is on, 41929649 of 41929649

(100%) updated sectors
28-Jan-2010 21:00:23 sbvol 101 successfully opened volume

\\?\Volume{138a9260-963f-11dd-bdfb-806e6f6e6963}
28-Jan-2010 21:00:23 sbvol 107 FAT system area sectors: 0
28-Jan-2010 21:00:24 sbvol 112 file \\?\STC_SnapShot_Volume_21_0\pagefile.sys

excluded OK
28-Jan-2010 21:00:24 sbcrypt 109 filter started
28-Jan-2010 21:00:24 sbfile 101 successfully opened file G:\Backups\C_VOL-b001.spf
28-Jan-2010 21:00:24 sbvol 107 disk MBR sectors: 1
28-Jan-2010 21:00:24 sbvol 107 first track sectors: 63
28-Jan-2010 21:00:24 sbvol 109 disk CHS 9726/255/63 partition 2
28-Jan-2010 21:00:24 sbcrypt 107 compression mode: 5
28-Jan-2010 21:00:24 sbcrypt 107 encryption mode: 3
28-Jan-2010 21:00:24 sbcrypt 600 Please enter the encryption password
28-Jan-2010 21:00:24 sptask 101 Answer was sent as UNICODE string
28-Jan-2010 21:04:04 sbvol 503 Fatal I/O error on \\?\STC_SnapShot_Volume_21_0

offset 37eb9e00 on read (-31 A device attached to the system is not functioning.)
28-Jan-2010 21:04:04 sbcrypt 500 Unexpected end of the image file
28-Jan-2010 21:04:04 sbfile 109 deleting the incomplete output file(s)
28-Jan-2010 21:04:04 sbvol 109 fini done
28-Jan-2010 21:04:04 sbcrypt 109 fini done
28-Jan-2010 21:04:04 sbfile 109 fini done
28-Jan-2010 21:04:04 (loader) 504 Final error (-31 A device attached to the

system is not functioning.)
28-Jan-2010 21:04:05 sptask 516 sbrun.exe started successfully but failed to

complete the task
28-Jan-2010 21:04:05 service 104 retry task
28-Jan-2010 23:14:08 service 105 snapshots were destroyed


Any advice?