I've pretty much spent hours upon hours trying to get the thing to run, and finally after JKJAL multiplayer works. But not single. It instantly crashes after bouncing on desktop for a while.
Excuse me?
Movie Battles is a strictly multi-player mod. It has no single-player at all. Neither on mac, nor on Windows.
You should be able to run Movie Battles multi-player, base Jedi Academy multi-player, and base Jedi Academy single-player, though.
Properly installed MBII doesn't break vanilla JA.