The Problem:

I'm trying to backup a SQL2000 cluster over the network using 2 maintenance
plans, one for 'simple' recovery DB's and one for 'Full'.

However for different databases I'm getting a mix of the following problems:

Event Type:       Error
Event Source:    MSSQLSERVER
Event Category: (2)
Event ID:           17055
Date:                10/07/08
Time:               20:04:48
User:                xxxx.xxxxx\SQLAdmin
Computer:        xxxxxSQLSVRxx
Description:
18210 :
BackupDiskFile::RequestDurableMedia:  failure on backup device
'\\xxxxxxx\d$\SQL_Backups\xxxxxQLSVRxx\FirstClass\FirstClass_db_200807102001.BAK'. Operating system error 64(error not found).

and

Event Type:        Error
Event Source:     MSSQLSERVER
Event Category:  (6)
Event ID:           17055
Date:                10/07/08
Time:                20:04:48
User:                xxxx.xxxxx\SQLAdmin
Computer:        xxxxxSQLSVRxx
Description:
3041 :
BACKUP failed to complete the command BACKUP DATABASE [exchangeDB] TO  DISK
=
N'\\xxxxxx\d$\SQL_Backups\xxxxSQLSVRxx\exchangeDB\exchangeDB_db_200807102001.BAK' WITH  INIT ,  NOUNLOAD ,  NOSKIP ,  STATS = 10,  NOFORMAT

and

Event Type:        Error
Event Source:     MSSQLSERVER
Event Category:  (2)
Event ID:           17055
Date:                10/07/08
Time:                20:04:48
User:                xxxx.xxxxxx\SQLAdmin
Computer:         xxxxSQLSVRxx
Description:
18210 :
BackupMedium::ReportIoError: write failure on backup device
'\\xxxxxxx\d$\SQL_Backups\xxxxSQLSVRxx\exchangeDB\exchangeDB_db_200807102001.BAK'. Operating system error 64(error not found).

Once I've censored the local details of the SQL log I'll post that as well.

Some of the (smaller) DB's covered by the same plans are in deed backing up
nicely, which adds to my confusion. I think the errors are stopping the job
from continuing so that the clean-up process of deleting older files isn't
running for any DB's.

My System:
Windows 2003 Enterprise Sp2 Cluster
Running SQL 2000 Enterprise sp4
2 Nodes - Using a FC connected 'HP MSA1500' as shared storage, trying to
copy to a Windows 2003 Enterprise sp1 server using a local attached SCSI
array.

Neither SQL nodes are running any AV products.

What I have tried so far:
Split the maintenance plans between 'simple' & 'full' recovery mode DB's. I
know they can be a bit bugged when covered by the same maintenance plan.
Ensured that the 'SQLAdmin' account has full control on the destination
files & folders.
Found & then discounted the following KB article as the version of the Hot
Fix has been superseded by a later Service Pack.
http://support.microsoft.com/kb/843515

I haven't tried creating a Share on the backup server, I was going to try
that next to see if that made any difference.

If anyone can dispense some wisdom to try & solve this I would be Hugely
Grateful.
Thank you in advance.