i cant use the "mx" class (450)

[osif481 (A)]

when the screen shows up to pick what to ride i.e. mx lite, mx or atv. when i hit the down button to select the "mx" class it shuts down my game. please help i'd like to race the beta tracks on the 450. thanks

[osif481 (A)]

i tried to uninstall and reinstall. didn't work. please help

[mcm2boys]

SOunds like you don't have all of the files installed, what are you using o install Steam or a CD?