hitTest problem. URGENT

i have created hitTest function.
it works in very strange way. It dosen’t work on every time I hit Ctrl+Enter.
Some hitTest work and some time it dosen’t work. I am realy getting frustrated. Even It dosen’t work in all browser. Some time it works in opera and some time don’t. For the FF not a single time.
here is the code:-

this.onEnterFrame = function() {
    if (this.black.hitTest(_root.huttest)) {
        trace("hit done");

What is the possible reason behind this. This hitTest working like having luck and bad luck.
thanks for your time.