Actionscript Question

Hello all…

Could anyone tell me why this piece of code works in Flash Player 7 but not in Flash Player 8?

duplicateMovieClip("drop", "drop" add a, a);
setProperty("drop" add a, _x, random(550));
setProperty("drop" add a, _y, random(400));
a = a+1

I keep getting the following error message:

Error Scene=Scene 1, layer=Layer 2, frame=2:Line 1: ‘)’ or ‘,’ expected
duplicateMovieClip(“drop”, “drop” add a, a);

Thanks for any help,

David