It seems to be from setting the layer scale too large. You're increasing the layer 1 scale as the window size shrinks. Just put 'on start of layout: set layer 1 scale to 100' and you get the same error. Maybe there should be some limit to layer scale?
<img src="https://dl.dropbox.com/u/8367729/construct/pics/layerScaleFirefoxError.png" border="0" />
<img src="https://dl.dropbox.com/u/8367729/construct/pics/layerScaleChromeError.png" border="0" />