Have errors from your skin or weapons .nob you so painstakingly created? Here are a couple of things I've found that cause problems.

Check the .not file to be sure that you have not instructed it to use a file that is not actually present in the .nob. Leaving out any files can cause your game to crash or lock up.

Be sure that the name in the .npm file is the same as the name of the template in the .not file. For example, if you name a character MP_Joey in the .not file, you have to name it MP_JOEY in the .npm file as well.

If you're using a custom model you've made, be sure there are no unassigned vertices. (In Milkshape go to wireframe mode, click Joints tab, and click SelUnassigned button...see my Milkshape tutorial for more info.)