no problem with 4.0 Rated 5 out of 5 stars
Hi, I try run this version on FF 4.0 and no problem.
It's to easy. Download xpi file. rename extenzion to .zip,
uznip and in file "install.rdf" change 5. rows from end to
then must all file add to zip again, rename to xpi and open in FF4. It is works fine