New Windows 7 machines hang at “initMPS with licenseOption 0”

We have a bunch of new Windows 7 workstations licensed with Maya. I’m attempting to add them into our Muster 6.x render farm. The machines are licensed, and render locally with Mental Ray for Maya, no problem, as well as from a locally issued command line. But when I attempt to render frames from Muster, the render log shows the scene loading normally, but it hangs, with no further progress, (or any frames rendered) at the moment the log comes to “initMPS with licenseOption 0”

As I said, the machines are licensed to run Maya, and MR for Maya runs fine on them, but the jobs die when submitted by Muster. Unfortnately, no more useful log is being generated – see below — that I can pick apart. Any idea what would cause the chunk to die at this stage of the render? I suspect network permissions, firewall, etc., but can’t sort out what’s causing it.

Thanks.

>>>>>>>>>>>>>

File read in 9 seconds.
Warning: Fluid initial state cache file ‘quadro_fermi_WMFG_v08.mb_fluidShape3.mcfi’ not found
Warning: This file contains an uncached fluid; rewind and playback to see correct current state.
Result: R:/swagstaff/2010_Quadro_Fermi_KV/scenes/quadro_fermi_WMFG_v08.mb
Warning: Found camera shotCamShape.
Error: particle1: Object not found for -object flag.
Error: particle1: Object not found for -object flag.
initMPS with licenseOption

>>>>>>>>>>>>>>>>