Model exporting

I'm getting in to XNA at the moment and I'm having a problem importing
animated models in to XNA:-( I'm using the KiloWatt animation library, but
my main issue is that I cannot export models from 3ds max effectively. As
a test I have created a 3ds max project, and created a simple biped.
then I attached a couple of spheres to the bones and made the legs
move. I set the model.fx shader in Max as the shader used for this
model, and exported it using the KW exporter. This approach worked
absolutely fine. So I went back to the max file and added a new object
(slightly more complex this time, a wheel with a tyre tread) which I
imported from an existing project that I am working on using merge in
3Ds Max. When trying to preview this model in the AnimationViewer tool
that was in the library, Visual studio crashes and restarts itself, or
it throws an error:

"Could not read the X file. The file is corrupt or invalid. Error code: D3DERR_INVALIDCALL."

When visual studio allows me to debug, I can see that an error is
thrown at line 334 of the Keyframe class. I desperately need to know
if there are any guidlines that I should be following to create
complex models so that they will work with KW exporter. If anyone can
help me I would really be so appreciative!

That's surprising. Visual

That's surprising. Visual Studio really shouldn't be crashing.
Does the file view properly in the DirectX Viewer application that comes with the DirectX SDK?
Is there an error log created on export, and if so, what's in it?

A more basic problem

Hello, I'am trying to get my 3D Max model into XNA, but I can´t even make work the simple tests, I'd really appreciate if you send me a copy of your working model, my mail address is alderick84@hotmail.com

Thanks a lot¡¡¡¡