Backup Fails In Windows Server 2003 For Small Business Server

Hi

MS Backup in Microsoft windows server 2003 for small business server reports:

<-- Volume shadow copy creation: Attempt 1.
"MSDEWriter" has reported an error 0x800423f4. This is part of System State. The backup cannot continue.

Error returned while creating the volume shadow copy:800423f4
Aborting Backup. -->


The VSS events that I get are 8193 & 6013
The MSSQL$SHAREPOINT events are 17055, 18452 & 18456


These are the main Errors that I get:

Event Type: Error
Event Source: VSS
Event Category: None
Event ID: 8193

Description:
Volume Shadow Copy Service error: Unexpected error calling routine IClientVirtualDevice::GetCommand. hr = 0x80770004.


Event Type: Error
Event Source: MSSQL$SHAREPOINT
Event Category: (2)
Event ID: 17055
User: NT AUTHORITYSYSTEM
Description:
18210 :
BackupVirtualDeviceFile:repareToFreeze: failure on backup device '{74A09E78-8845-47EB-9602-705E4406096C}1'. Operating system error 995(The I/O operation has been aborted because of either a thread exit or an application request.).



Event Type: Error
Event Source: VSS
Event Category: None
Event ID: 6013
User: N/A
Description:
Sqllib error: OLEDB Error encountered calling ICommandText::Execute. hr = 0x80040e14. SQLSTATE: 42000, Native Error: 3013
Error state: 1, Severity: 16
Source: Microsoft OLE DB Provider for SQL Server
Error message: BACKUP DATABASE is terminating abnormally.



Event Type: Error
Event Source: MSSQL$SHAREPOINT
Event Category: (2)
Event ID: 17055
User: NT AUTHORITYSYSTEM
Description:
18210 :
BackupVirtualDeviceFile:repareToFreeze: failure on backup device '{74A09E78-8845-47EB-9602-705E4406096C}5'. Operating system error 995(The I/O operation has been aborted because of either a thread exit or an application request.).


I need to get the Backup System working again urgently.
Any advice will be greatly appreciated