m4v untitled chapter

i am running itunes on a mac mini with snow leopard. i am at the most recent version (10.4 I think was the number). I have a bunch of M4V movies on there. I now am not able to go between chapters in the m4v movies. Sometimes the chapter will show up, but instead of having the name they are titled 'untitled chapter'. Some m4v movies will not allow me to see the chapters at all.

I did install Cienega on there (which never did work) maybe that has something to do with it, but removing the program has not helped.

I also tried to have itunes rebuild the library and that was not helpful.

i also tried to delete all the files from the itunes cache and that did not help.

Any help would be appreciated.