1st thing I'd try is getting rid of the Director track if you're not going to use any camera. The director track is only useful in cut-scenes anyway, and it could potentially cause issues to have it empty like that.
If all of the other trackviews work fine, I'd suggest verifying that the node that triggers that particular sequence isn't to blame. For instance, link the output of the Vehicle:Enter node to a Debug:DebugDisplay node and have it show something, whatever. That way you'll know for sure if that node actually outputs something in pure game. It happened in the past that some nodes, for some reason, don't output properly in pure game.
If that doesn't solve it for you, here's a few other things that pop to mind:
- check that the sequence entity (look for an entity of the same name as your trackview sequence) isn't on a No-Export-To-Game layer.
- instead of triggering that particular sequence, trigger another one of your sequences that work fine. If they don't start either, that means the problem is not the trackview itself but the setup/trigger/etc. If it does work with another trackview, then it probably means that that particular trackview is to blame, and it could be worth creating a new one and duplicating the tracks in there, just to see if it solves the problem.
Good luck! Identifying the source of the problem is the first step. Solving it is usually easy then 
