Arithmetic Exception keeps being thrown from Farseer

Aug 24, 2008 at 1:59 AM
I get this error:
"Function does not accept floating point Not-a-Number values."

On this line of code in Body.cs:
rotationalDrag = angularVelocity * angularVelocity * Math.Sign(angularVelocity);

It seems to occur randomly when a set of bodies held together by RevoluteJoints crashes into an object.

Why would this happen, and how can I prevent it?

Thanks.