AS3 My flash object is making browser unresponsive overtime

[x-death]

well everytime a button is pressed you create a new variable for your tweens. while this isn't the source of your problem its not the best thing to be doing. uptop of script i'd write:

var variableName:Tween;

then in your button listener function were your using this tween. you can just write:

/* just made the inside of the function dots as 
i'm not going to write it for you, you already 
know what your putting in there.*/
variableName = new Tween(....);

i can't seem to find the actual source of your problem. anyways hopefully this has helped you to some degree.