So the only diff between your in Maya render and your batch render is the image plane I guess. Does it render properly in Maya without the image plane?

I'm not a big fan of Maya's IBL. Not sure if they got it fixed in Maya 8, but it causes all sorts of problems in Maya 7 and is almost useless with render layers. I could easily see it being the cause of your problems but I have no idea why. Try removing it and seeing if your renders start looking the same in Maya and with the batch renderer.