I opened a case for something similar last year. In the end we upgraded to 7.0 which seemed to resolve the issue. Although it subsequently has come back (I need to repopen the case). There were a number of things that we worked through. At the time I was seeing this logged during the backup::
20/01/2011 15:22:48 - Error bpbrm(pid=3620) from client dc3: ERR - Error encountered while attempting to get additional files for System State:\
20/01/2011 15:22:55 - end writing; write time: 00:03:59
the requested operation was partially successful(1)
The following hotfix seemed to be one:
http://support.microsoft.com/kb/955012
Also I rember that the particular DC we were trying to backup we found had some corruption in its AD database (it failed in the end). We switched to a different DC.
I can also see that at the time an EEB was produced for version 7.0 that we installed. Its EEB 2143811 this was specifically for the expansion of the system state when doing a restore. I'm not sure how much help this is to you given that you are running 6.5.4
Hope this helps
Mark
