Illustrator CS6 Gradient Tool is causing program to crash very often.

I import cleaned up, flattened and contiguous .dxf vector data from my CAD modeller, create live paint areas and then render the boats I design.  Simple. 

Typically the artboards are D-Size (36 x 24).  About 50% of the time I try to use the gradient tool to shift a gradient around, it will lock up the program and boot me straight out to the desktop. 

I'm forced to save after every successful art-change to prevent losing time and ground on this.  This is the only issue I'm having with CS6 (I had the same problem with CS5 too).

This is a CAD system I'm using.  (W7-Pro, 3.5 ghz Intel Quad-Core, 16gb ram, NVidea Quadro 4000,).

I'm happy to post the actual file in exactly the spot I'm at where it'll crash.

Thoughts anyone?

Thanks

Michel Berryer

Van Dam Custom Boats