This is a tricky one. I have had to waste a lot of time. The trick is to use 32bit browser (extract firefox into $HOME/firefox and run it from there. Details below), and a full JDK package from Sun. JRE is not good enough!
I have a $HOME/bin/firefox32 script which looks like this:
exec “$HOME/firefox/firefox” -P 32bit -no-remote “$@”
I have created a dedicated profile called “32bit” to which I call with the ‘-P’. Also – setting no-remote prevents firefox from adding an additional window on an existing firefox currently running.
In the profile directory ($HOME/.mozilla/firefox ) create a directory called ‘plugins’ and create a symlink in it to the JDK installation plugin’s location. Works, as I have mentioned before, only with the full JDK package. This was the difference.