Buggy but promising.
A nice early work, however, as previous people have noted, there's a problem with how you have the preloader setup.
If you are (as you appear to be) using the Newgrounds preloader, this problem shouldn't be happening at all unless you've tried to change the code from the preloader.
(Guys, if you want to review this game, you can right-click and select "Forward" until the music starts, and the rest of the code works fine.)
The collision detection for the asteroids is clunky -- they record collisions when there's a good quarter inch of screen between my ship and them.
A few muted sound effects wouldn't hurt.
The music loop that plays during the race is, well, not good for gameplay -- wouldn't be bad menu music, but it's entirely too repetetive for the game itself.
Wrapping around the screen is something most games avoid for a reason -- it's not exactly intuitive.
What's the condition for ending the race? Number of asteroid collisions? Time spent? What?
But mostly, your code is solid and you show promise.