Problems Rendering Volume Lights in Mental Ray
I created a small volume light shining inward to provide a low-visibility view on a character traveling through a cave, but whenever I try to render it in a sample frame, I get this message: Warning: file: C:/Program Files/Autodesk/Maya2013/mentalray/scripts/mentalrayUI.mel line 182: (Mayatomr.Script): more than one mentalray globals node found, using just the first Simple_Model:mentalrayGlobals //
I thought the light wasn't working, as the preview when I turned on, "Use all lights," showed pitch black, yet when I tried to import a torch I had from an old scene that used another volume light to generate a similar effect, the loading caused me to see for a split second that the light and its effects WERE present. I'm not entirely sure where to go at this point, so I come to you guys for help.

Thanks,
-Connor