You need IOS57 or 58 (I can't remember which) for Just Dance. Most games run with IOS56 but a few like COD, microphone games and Just Dance need newer ones.
The recommended d2x cIOS configuration to cover everything:
IOS249[56]
IOS250[57]
IOS251[58]
Just leave the loader on 249 except for the games that won't run on it. All current loaders should let you override the default one per game.