duplicateMovieClip wont duplicate!

Working on FL8 AS2

Hello all, I’ve always had a problem getting the duplicateMovieClip to work properly… So here’s my code:

for (i=0; i<_root.level.length; i++)
        for (j=0; j<_root.level*.length; j++)
            if (_root.level*[j] == 1)
                setProperty(_root.block0, _x, j*10);
                setProperty(_root.block0, _y, i*10);
                duplicateMovieClip(_root.block0,"temp"+i+j, 0,);

In theory…for each pass shouldnt it:

Reposition block0’s x and y
duplicate block0 on that position.
move on

but it seems only the setProperty works because my block0 eventually ends up at the last position. Can anyone help me duplicate it properly? Any help is appreciated. Thank you.