I am having some difficulties with some WordPress files throwing a "Components is not defined" error in Firefox.
That is e.g. tw-sack.js and wp-gears.js.
They both try to create an ActiveXObject (for IE, I guess), which does not seem to work with Firefox.
I have posted about this here:
Please also see the comment section.
Maybe someone knows the reason for the error and/or a solution?