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It's not mentalray that's crashing, it's actually a part of Maya regarding geometry. Try running the mentalray diagnostics, and see if it pops up any warnings.
Did you run the mentalray diagnostics? http://download.autodesk.com/us/maya...mber=d0e582893
You have some bad geometry, as it says on these lines: Which makes sense, as your previous crash log says it has something to do with geometry as well. What you can do is select your geometry, and export it as an OBJ file, which saves just the geometry data. Create a new scene, and import it back in. This will clean out any bad geometry. Now, try rendering the newly created file. It should render just fine.