All the coding is done in Visual Studio 2010 Express, on a Windows 7 machine, using XNA 4.0 Refresh. I have my own custom Animation Writer and Reader.
Here is what the beginning frames of the animation look like:
And this is the pose that he gets stuck in for 15 seconds:
I've attached my AnimatedModel class in case somebody would like to take a look at it. Anybody has any idea what the problem might be?