Maybe you should provide more info about your problem? Screenshots, what OS you have, is there any error messages, what exactly you've downloaded, etc. Also check your firewall, if any; maybe it blocks game to connect servers.
You can try manual install:
1. Install Jedi Academy.
2. Download Star Wars: Movie Battles II v1.3.1 download . Unpack it to your Jedi Academy\GameData folder so there will be such path: C:\Program Files\JediAcademy\GameData\MBII
3. Download
http://www.moviebattles.org/download/servers/V1.3.1_V1.3.2_Upgrade.zip . Unpack it to same folder as N2 overwriting files with same names.
4. [Optional] You also will need some minimizer to make switching to other apps possible. You can use this: JA Minimizer . Run it before run game. You will be able to use F11 key to switch between mb2 and other tasks.
5. Start the game by launching file C:\Program Files\JediAcademy\GameData\Play_MBII.bat
Works for me.