A better executable to use to start firefox from the command line is "/usr/lib/firefox/firefox" instead of "/usr/lib/firefox/firefox-bin". THe former is a shell script that setup some environment stuff and then call the later.
Does /usr/lib/firefox/libmozjs.so exists on your system? It should be there, and on my system, it is installed via that same firefox package that you have on yours computer: $ ls -l /usr/lib/firefox/libmozjs.so -rw-r--r-- 1 root root 620708 2006-09-21 03:27 /usr/lib/firefox/libmozjs.so $ dpkg -S /usr/lib/firefox/libmozjs.so firefox: /usr/lib/firefox/libmozjs.so $ apt-cache policy firefox firefox: Installed: 1.5.dfsg+1.5.0.7-ubuntu0.6.06 Candidate: 1.5.dfsg+1.5.0.7-ubuntu0.6.06 Version table: *** 1.5.dfsg+1.5.0.7-ubuntu0.6.06 0 500 http://security.ubuntu.com dapper-security/main Packages 100 /var/lib/dpkg/status 1.5.dfsg+1.5.0.3-0ubuntu3 0 500 http://archive.ubuntu.com dapper/main Packages ** Changed in: firefox (Ubuntu) Status: Unconfirmed => Needs Info -- libmozjs.so not found on Dapper Install https://launchpad.net/bugs/64577 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs