hmm...strange :-/
There is indeed a "hidden" check function but only to catch conversion errors, not basic "it's not converting at all" - errors. It's pretty old and I didn't use it for a while, so I'm not sure if it's still working as expected. You can activate this function with editing the scriptfile:
Set this line to true (right at the beginning of the file, after the comments. It will print some stuff in the listener if there is a problem.
CorConvDEBUGmode = false -- Set this to true if there are any problems with converted Materials and re-run converter with orig. Materials
I'm, however, pretty certain that there must be some other problem here. Is the Script running correctly? Any popup errors or some red stuff in the maxscript listener (the pink field in the bottom left corner)?
Be aware that the Script currently only covers MR_ArchAndDesign & MR_Carpaint (concerning mental ray) If you use any other specific mental ray stuff it will be ignored.