How can I make a function out of this

Im trying to set a mask consisting of 9 squares and want to make a function that creates the squares out of th e following, that works in it self

mask_mc.createEmptyMovieClip("block1", 31);
bgcontainer(mask_mc.block1, 66, 66, 1, 0x000000, 100);
mask_mc.block1._x = 66;
mask_mc.block1._y = 66;

so I created a function looking like this:

function maskBlock(bDepth, bWidth, bHeight, bX, bY){
      var newBlock = "block" +bDepth;
      var newDepth = "3" +bDepth;
      mask_mc.createEmptyMovieClip("block" +bDepth, newDepth);
      mask_mc.newBlock._x = bX;
                     mask_mc.newBlock._y = bY;
      bgcontainer(mask_mc.newBlock, bWidth, bHeight, 1, 0x000000, 100);
}
maskBlock(1,66,66,0,0);

but that result in that I get an error saying that there is missing a 'with' action

What is wrong and how should I do it right....