hmmm, anyone investigating this to give input, check the settings on the Tools.. Internet Options.. Advanced... and the Disable Script Debugging and Dsable error notification.
Sill me, I had it turned off from previous supprot I was giving someone.
( Reminder to self ... when walking it through with a "customer" remember to turn your own one back )
For most users you want these boxes ticked as after all who cares about odd-ball errors if it doesnt' affect the web page.
FF is handling it 'better' and by default FF doesn't tell you about any script errors and expects you to play with the JavaScript console.
Another example of why having too many options can be a problem !
If you tick the boxes in IE it will avoid the error for everyone hitting it until I can discuss why it's making the call anyway
"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'