If it’s urgent and you are not using 21 anymore you can simply remove that code.
Update: I’ve removed a batch-mode hack that is not working for users.
Also, if you’re not using any advanced features you can try submitting with “batch mode” disabled in the submitter.
Update: I’ve been doing some digging into other tickets and even if not rendering in batch mode, you would need to backup then modify “[repo]/plugins/MayaCmd/MayaCmd.py” and replace “-r rman” with “-r renderman”:
rendererArguments += " -r rman"
to
rendererArguments += " -r renderman"