Flash nav for site randomly shifting

Hi all,

www.h2sr.com

If you click on the flash nav in IE7, occasionally the logos within will shift hard to the right. I can't seem to come up with a pattern for this, but here is the very basic script on each of the MC's:

Code:

Code:

---

this.onEnterFrame = function(){
        if(rewind == true){  //if rewind switch is set to true play backwards
                prevFrame();        // play backwards
                _parent.prevFrame();
                skewed_mc.prevFrame();
        }
}

this.onRollOver = function(){
        rewind = false; //set variable (or switch) that decides wether ot not to play backwards...
        play();    // play this movie clip.. (grow the button(tween))
        _parent.play();
        skewed_mc.play();
;
}

this.onRollOut = function(){
        rewind = true;    //set or rewind switch to true so it will play backwards...
}
stop();

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A level above that code is a simple getURL on one layer:
Code:

Code:

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strip_mc.onRelease = function(){
        getURL("?page_id=490");
}
As well as a layer with a stop on frame 1 and 10.

I have been pulling my hair out like crazy over this... any inklings of an idea would be hugely appreciated.

---

Thanks!