Hey Gametoast,
At the moment I have a big issue with a character model. Currently he is divided into some parts (body, eyes, hair..) and then I export him as a .msh file in mshviewer I can see him as a 3 dimensional model. But then I add the head model (from the xsi model template; xsi man model), delete the whole body (but not the head) and add the head on my character's body and then I export him (It still works) the mshviewer (Then I open the model) doesn't work anymore and I get this popup window: An exeption of Class OutOfBoundsExeption was not handled.. After that the mshviewer closes itselfs.

I don't know why that is happening. Without the head model it still worked. And if I just export the head (or even the face model) it still crashes the mshviewer. And then I even munge the chararacter the pc_Modelmunge doesn't work either.
I hope someone know where the problem is.
Are there any important setting I may reset?

That head mesh is way too high-poly and ZETools probably wrote out a corrupt msh file because of this. Run the 'Polygon Reduction' tool on it and it works fine.

Wow thanks. It works fine now. I have also forgotten that I reduced the poly count of an other character today. And it worked there. Again thank you!

The mshviewer will have that error pretty much any time you ask it to export a model that has...issues,
such as when there's surface geometry folded in on itself in a physically impossible manner, for example.
Of course, it seems to have the problem with certain objects that are just way overly complicated, too.