Firefox 8.0.1

Ivan,
We've never heard of that error, but doing a quick Google search brought me to the post below. The users there seem to indicate that it's a bug in Firebug itself, not a 'real' Javascript error:
stackoverflow.com/questions/8251540/unca...proxy-installtrigger

Hope that helps, but if not, let us know. Not sure of any other suggestions.

Thanks,
Alex