SQL Server 2008 :: Backup To Device / UNC File / Generates OS Error

It's OS / SQL related. I backup to a UNC device, and frequently get a network related error - but not always. And the error is also OS related...

The scene: 64 bit Windows Server 2008 hosts 64 bit SQL 2008 Standard, and devices are created to point to 64 Server 2008 Server B (ServerBSQL_backupsdvc_DB.bak). The database is backed up daily, on a job, and when run the following error is returned:

Date2009/08/08 06:43:30 AM
LogJob History (Backup_AssetData_2009-08-08)

Step ID3
ServerSQL01
Job NameBackup_AssetData_2009-08-08
Step NameBackup Database - Second Attempt
Duration00:05:33
Sql Severity16
Sql Message ID3013
Operator Emailed
Operator Net sent
Operator Paged
Retries Attempted0

Message
Executed as user: COMPANYSERVICE_USER. Processed 94096 pages for database 'AssetData', file 'AssetData' on file 1. [SQLSTATE 01000] (Message 4035) Processed 1 pages for database 'AssetData', file 'AssetData_log' on file 1. [SQLSTATE 01000] (Message 4035) The operating system returned the error '64(failed to retrieve text for this error. Reason: 15105)' while attempting 'FlushFileBuffers' on 'dvc_AssetData(
iscsrv-dcm04RISCSRV-SQL01_Backupsdvc_AssetData.bak)'. [SQLSTATE 42000] (Error 3634) BACKUP DATABASE is terminating abnormally. [SQLSTATE 42000] (Error 3013). The step failed.

The file is generated, the same size as a successful backup, but the job terminates unsuccessful.I have tried to delete the devices' file, and then the backup usually succeeds. This may point to a permissions' type error, but the user the job is run under is a domain admin. The destination server is not unavailable during this time, and the network shares also remain active throughout the excersize - although I haven't got a way to "prove" this.

I have a few databases that backup to the UNC described above (different files) that don't fail..My SQL2000 server backs up it's databases to the SQL2008 server, and those backups don't fail with this error.

My research has led me to understand that the 64bit OS tries to buffer the files it receives from another server, and I was wondering if this could be influencing the backups as the destination server is also 64 bit Windows Server 2008.

##20090812## UPDATE

I tried another way to do the backup; with the same results:

Backup database Infovest to disk = '
iscsrv-dcm04
iscsrv-sql01_backupsdvc_Infovest_Z.bak' with INIT,STATS=1

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