I think the problem may have been with the size and/or content of the Poser file. QM can handle a simple render, but it failed for a Poser render with a 60MB pz3 file and a 105MB pmd file.  The log entries are:

...adding new Queue entry id 1
Queue Procs now available: 0
Launching FFRender for parsing...
C:\Program Files\Poser Software\Poser 12\FFRender64.exe "C:\Program Files\Poser Software\Poser 12" "C:\Users\Public\Documents\#########\2022- 3-12_17h47m11s.pz3" "C:\Users\wtang\AppData\Local\Temp\Queue Manager\12" "2000" "1600"
... FFRender launched
Parser process is ready to talk
SetRequestedFrame OK
Parser assets are ready.  Updating qTask with filenames.

Then the error message appears.