Issues backing up / restoring.

we are currently having issues with backing up and restoring using redgate 6

This is on a Windows server 2008 R2 Standard 64-bit with SQL Server 2008.

the error in the log is:

23/02/2010 10:56:18: Backing up master (full database) to:
23/02/2010 10:56:18: F:\MSSQL\LOGS\FULL_(local)_master_20100223_105618.sqb

23/02/2010 10:56:18: BACKUP DATABASE [master] TO VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA35', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3501', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3502', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3503', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3504', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3505', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3506', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3507', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3508', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3509', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3510', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3511', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3512', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3513', VIRTUAL_DEVICE = 'SQLBACKUP_06AAA08C-24AA-4B1D-93FD-9D29F1CDAA3514' WITH BUFFERCOUNT = 30, BLOCKSIZE = 65536, MAXTRANSFERSIZE = 1048576, NAME = N'Database (master), 23/02/2010 10:56:18', DESCRIPTION = N'Backup on 23/02/2010 10:56:18 Server: LRS019 Database: master', FORMAT

23/02/2010 10:56:48: Warning 200:
Warning 200: Error creating backup file: F:\MSSQL\LOGS\FULL_(local)_master_20100223_105618.sqb.
Warning: System error 5 (Access is denied)
23/02/2010 10:56:48:
23/02/2010 10:56:48: Warning 605:
Error 605: Error creating backup file(s). No files could be created.

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UAC is turned off completely and i've even tried elevating the permissions of the relevant user to admin to ensure that its not a permissions issue but i still get the same thing.

we are also getting the following errors in the event log

BackupVirtualDeviceFile::RequestDurableMedia: Flush failure on backup device 'SQLBACKUP_DF0272DA-CA84-4746-A91C-1E427D0F3CE914'. Operating system error 995(failed to retrieve text for this error. Reason: 15105).

and

SQLVDI: Loc=TriggerAbort. Desc=invoked. ErrorCode=(0). Process=1928. Thread=2108. Server. Instance=MSSQLSERVER. VD=Global\SQLBACKUP_DF0272DA-CA84-4746-A91C-1E427D0F3CE9_SQLVDIMemoryName_0.

There is loads of room on the server on all drives on the server so its not a space issue, and its a fresh build. I can restore or backup using SQL native backup to the same drives with no issues.

Any suggestions would be greatly appreciated as we're putting alot of these servers live and really need to bottom this out.

Thanks very much