Scale9grid error for left scale

I have an MC with the registration point set to the Top Right so it will scale down and left:

function dragMC(e:Event){
my_mc.width = Stage.width - mouseX;
my_mc.height = mouseY;
}

The MC i want to drag and scale has the following coords:

my_mc.x = 636.65;
my_mc.y = 44.5;
my_mc.width = 146.1;
my_mc.height = 108.6;

Im getting an error because of the settings for :

var grid:Rectangle = new Rectangle(10, 10, my_mc.width,my_mc.height);

Can anyone spot prob what im stupidly doing wrong! :slight_smile:

Any help comments appricated!

Trez