Realistic Star field effect in Flash

I made a movie clip called star, drew a small white dot, and places it on my stage.
I copied this code to my actions layer in frame 1 and this is the errors i get:

**Error** Scene=Scene 1, layer=actions, frame=1:Line 11: ';' expected
for (i=0;i {

**Error** Scene=Scene 1, layer=actions, frame=1:Line 12: ':' expected
star_field[i] = new star(random(400),random(200),random(speed)+1);

**Error** Scene=Scene 1, layer=actions, frame=1:Line 13: ')' or ',' expected
duplicateMovieClip ("star", "star_" add i, i+10);

Total ActionScript Errors: 3 Reported Errors: 3

I really dont get what is wrong...
Can anyone help me? Am I missing something?