Error #1502 (script ran too long) thrown when using dynamic border metrics in a GraphicRectangularBorderSkin

I have a skin that's base clas is GraphicRectangularBorderSkin (from degrafa). I'm using it as a panel skin. I'm using Degrafa 3.2, Flex 3.2. It throws a #1502 error (thrown when a script runs too long) every time. If I remove the line changing the em variable, the error goes away.

The class is basically (although I paraphrased for the sake of clarity):

<GraphicRectangularBorderSkin xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="http://www.degrafa.com/2007>
   <geometry>
      <GeometryComposition>
          <RegularRectangle width="{skinWidth}" height="{skinHeight}">
             <fill>
                <SolidFill color="#00ff00" />
             </fill>
          </RegularRectangle>
   </geometry>
   <mx:Script>
     <![CDATA[
        import mx.core.EdgeMet开发者_开发问答rics;

        private var em:EdgeMetrics = new EdgeMetrics(0, 0, 0, 1);
        private var headerHeight:Number = 0;

        public override function styleChanged(styleProp:String):void{
             headerHeight = getStyle("headerHeight");
             em = new EdgeMetrics(0, headerHeight, 0, 1);// if i remove this line, the error goes away
        }

        public override function get borderMetrics():EdgeMetrics{
             return em;
        }
 ]]>
</mx:Script>
</GraphicRectangularBorderSkin>

So apparently you need to use GraphicPanelSkin as the base class and it'll take care of the borderMetrics for you.

Documentation here: http://www.degrafa.org/docs/com/degrafa/skins/GraphicPanelSkin.html