Networker backup with Exchange module fail

Hi,

I make a new installation of Networker 7.6.1 with Networker Exchange Module 5.1.3:

The backup server is in a Windows 2003 server.

And, the costumer had a Exchange Cluster, with 3 physical nodes and 2 "virtual" nodes. This are in a Windows 2003 with Exchange 2003. There are Storage Nodes, with backup to disk devices.

We do all the configuration to backup both virtual nodes, but in a certain time, the backup exit with the follow error:

43621:nsrxchsv:Computer Name: MXHMXEX003     User Name: SYSTEM

52708:nsrxchsv:nsrxchsv_ese.exe Version: 5.1.3.274 Supporting Exchange 2000, Exchange 2003 and Exchange 2007

52702:nsrxchsv:System Version: 5.2 Build 3790 S

52708:nsrxchsv:ESEBCLI2.DLL Version: 6.5.7638.1 Service Pack 2

46896:nsrxchsv:Performing an Exchange save operation; save level is Full (Legato Backup Level: full).

28930:nsrxchsv:Parsing parameters from the command line...

28912:nsrxchsv:Opening connection to NetWorker Server...

46757:nsrxchsv:Processing storage group "SG2"

46764:nsrxchsv:Backup storage group SG2 to mxhmxws036

46776:nsrxchsv:  Backup database: Mailbox Store 1  (MXHMXECL02)   {F5CC8A00-F527-4139-AEFF-C3898E3D8855}

28920:nsrxchsv:This program has been asked to exit.

28921:nsrxchsv:Performing orderly shutdown of the backup environment.

46779:nsrxchsv:Error saving file T for database Mailbox Store 1  (MXHMXECL02)

46774:nsrxchsv:The backup of SG2 failed; status is 0x000003e3.

46767:nsrxchsv:Completed backup of SG2  Status: 0x000003e3

  The I/O operation has been aborted because of either a thread exit or an application request.

46885:nsrxchsv:Backup operation finished with errors.  No savetime was sent.

43709:nsrxchsv:Stop time: Mon Nov 08 11:53:45 2010

Already tried with many user's and password, with the enough permissions for Administration of Exchange and the error is the same.

But when we do a test backup of file system's, as much in the virtual node as in the physical node, the backup finish without problems.

I hope someone can help me with this Issue.

Regards