I get the message "British English Dictionary could not be installed because it is not compatible with Firefox 4.0". I'm trying to install the most recent version, Version 1.19.1, dated December 5, 2010, and supposed to work with Firefox 2.0b1 - 4.0.*. The Release Notes state "This release updates the installer for compatibility with the new extension packaging format in Firefox 4 ". But still it won't install and I'm stuck with the US dictionary. Anyone got any idea why? I'm running Firefox 4.0 on Windows XP SP3