Nah, those are add on shaders, right?
Just forgot the icon on highend3d or something, I also have "missing *.xpm" style messages and they are only warnings, not errors. Try batch-rendering from the commandline
on windows:
Code:
mayarender_with_mr -file file.mb
(and remember to set
SET MAYA_INSTALL_PATH=C:\Program Files\AliasWavefront\Maya5.0 <-- to whatever your install path is)
If it persists, does MR work on all/any other scenes?