2003 Server VM Backup failing error code 128

I've tried to research this error code, but I'm only finding general OS-related Error code 128. We're running EMC Avamar v7.0.101-61. I have a pesky 2003 VM with the x86 Avamar Client installed that continues to fail, producing the following:

2015-05-19 18:00:14 Filesystem Backups-General Office Filesystem-1432076400037 Info <0000>: [ctl_spawn] Executable : C:\Program Files\avs\bin\avtar

2015-05-19 18:00:14 Filesystem Backups-General Office Filesystem-1432076400037 Info <0000>: [ctl_spawn] Args       : avtar --sysdir="C:\Program Files\avs\etc" --bindir="C:\Program Files\avs\bin" --vardir="C:\Program Files\avs\var" --ctlcallport="1052" --ctlinterface="3001-Filesystem Backups-General Office Filesystem-1432076400037" --logfile="C:\Program Files\avs\var\clientlogs\Filesystem_Backups-General_Office_Filesystem-1432076400037-3001-Windows.log"

2015-05-19 18:00:14 Filesystem Backups-General Office Filesystem-1432076400037 Warning <0000>: [ctl_spawn] Workorder "Filesystem Backups-General Office Filesystem-1432076400037" non-zero exit status 'code 128: There are no child processes to wait for'

2015-05-19 18:00:14 Filesystem Backups-General Office Filesystem-1432076400037 Info <0000>: [ctl_spawn]

Usually, with 2003 clients, we're able to just bounce the box and the backup completes successfully. This wasn't the case.

TechNet's definition of Error 128 says to contact software mfg...

Even though I rebooted yesterday, the backup still failed last night. Checked the logs and was seeing this Error Code 128 “There are no child processes to wait for”, which happens to be a fairly generic error and not specific to Avamar. I checked their forums and saw nothing posted. I performed a search for that error text and ran across this random, 3rd-party article that referenced editing the “SessionViewSize” reg key in order to provide more memory for each job’s non-interactive desktop, as documented on Microsoft KB 126962.

I edited the HKLM\System\CurrentControlSet\Control\Session Manager\SubSystems\Windows key. Using the guidelines on that MS KB above, I changed the “SharedSection” values:

For Windows 2000, Windows XP, and Windows Server 2003:

SharedSection uses the following format to specify the system and desktop heaps:

SharedSection=xxxx,yyyy,zzzz

For 32-bit operating systems, increase the yyyy value to "12288"; Increase the zzzz value to "1024".

I did not change the existing xxxx value.

After rebooting the server, two things happened:

1. 1. I did not receive the usual message I see at login, “one or more drivers failed to start”
2. 2. Avamar successfully completed an ad-hoc, manual backup.