One of our clients has been having issues with Volume Shadow Copy and SQL (MSDE) causing the backup to fail with the error 0x800423f4. By following the script at TazNetworks it looks like the backup might work tonight. It's too early to tell but at least when I kicked the job off briefly it started to some work rather than just quit out of ntbackup.
Update Unfortunately the solution didn't work for me, but I noticed that there was a hotfix available (904418) which is for x86 based operating systems. I noticed that they were trying to register the Sqlvdi.dll file, so I reran the registration of this dll (which wasn't in the original script above), restarted ntbackup and the system state backup worked ok which was great news as it wasn't working previously. I then kicked off the nightly backup to run though and it looks like it is working, so in short -
cd C:\Program Files\Microsoft SQL Server\80\COM
regsvr32 sqlvdi.dll
