Duplicate movie problem [renamed]

programming flash
1

i want to duplicate a movie clip b1 and create ball1 to manipulate them with setproperty, and the same for b2 but this one into ball2. when i execute this code it would only do it for b1 and not for b2. can anyone help???

[right]Julie(^_^)[/right]

var x1=50
var y1=100
var x2=60
var y2=89

duplicateMovieClip (this.b1,ball1,1);
setProperty(pelota1,_x,x1);
setProperty(pelota1,_y,y1);

duplicateMovieClip (this.b2,ball2,2);
setProperty(pelota2,_x,x2);
setProperty(pelota2,_y,y2);