I somehow managed to clear out the name of a 2D procedural texture when closing the editing window without realizing it. (I was editing an existing texture rather than creating a new one--I think.)
Everything appeared to work fine. Object was updated with modified texture. However, when I went to further tweak the texture, its name was no longer available (for selection) in any of the lists. I saved and closed the file, re-opened it, and the file itself loaded fine. However, the object on which the texture had been applied was listed in the objects list as "unreadable" followed by the object's name.
File in which the bad texture prevents object loading
Logged In: YES
user_id=74743
Originator: NO
I tried setting a texture name to be blank. It still shows up in the list, but thanks to a strange behavior in JList, it is only shown as a few pixels high. If you use the arrow keys to move through the list, you can easily select it. When I then saved the scene, it had no problems being loaded again.
I notice that the error in the scene file you posted occurs while loading a polymesh object. That makes me suspect a problem in the polymesh plugin (possibly that you created the scene with one version of the plugin, then tried to load it with another one?). I suggest posting it in the bug tracker at aoisp.sourceforge.net so that Francois can take a look at it.
Alternatively, if you can reproduce this problem without using a polymesh, please describe the exact sequence of steps to reproduce it.