mayabatch.exe reeks havoc (once more)

The rendering problem I've mentioned in this post has returned in Maya 2011!

The day lighting was completed and ready for render, I received the following error from Maya, when attempting to batch render:

// Result: Saving temporary file: D:/Projects/Zohar HaNegev/zoharhangev_project/scenes/UpperFloors00__4240.mb // 
// Result: Rendering with mental ray... // 
// Result: Rendering Completed. See mayaRenderLog.txt for information. //

Of course, Maya did not render a single frame…
A further look into the mayaRenderLog.txt reaveled the following message:

Starting "C:\Program Files\Autodesk\Maya2011\bin\mayabatch.exe"
QWidget: Cannot create a QWidget when no G// Maya exited with status 1

I've attempted several things in order to solve the error. Amongst which, were reviewing  the render globals trying different image formats, deleting Maya's preferences, disabling the Antivirus, and testing different scenes. I also posted the problem on several forums. The only advice I received was to contact Autodesk.

I decided to completely uninstall Maya 2011, and the older versions that I had on my hard drive (2009 and 2010), and re-install 2011by itself.

This seemed to solve the QWidget problem.

Unfortunately, mayabatch.exe returned to the original problem of 2009, where it would only use up to %50 of the cpu power to render (8 cores, 16 threads). To be accurate, it started  around the %13 mark, blasted up to %49-%60 for a short time and then hung at %22 for the reminder of the frame. I also noticed many unnesicary DAG calculations before each frame that lasted about 2 minutes and a very long hang time after each frame was completed. This meant that a frame that would normally take approximately 1:15 minutes, would now take around 6 minutes. These problems were not present before the reinstallation.

Maya still rendered single images in a timely manner, thus I will be providing playlasts, coupled with still images of the renders for now.

As of today the problem has not been solved.