Once you did that the "Ok" button should be blue but we are not done yet you are going to see "Command Line Options" you are going to type in "+set fs_game MBII" (Without parentheses) This will allow JKJALaunch to launch Movie Battles right when you launch multiplayer.
Have you done this step?
JA: v188.8.131.52 win-x86 Oct 24 2003
Initialising zone memory .....
----- FS_Startup -----
ERROR: filename length > MAX_QPATH ( strlen(models/players/pl_rockettrooper/base_rockettrooper_rocket_spec.jpg) = 66)
I get this error when trying to launch beta