I don't think java is causing firefox to crash. I suspect there is something wrong with firefox itself.
From what I can see from your post, I don't think you created the simlink correctly. I'm using the same version of java without problems. I'm running it on Mandriva 2008. Soem things to verify. When I did a locate for libjava, here is what I see on my system.
Code:
locate libjavaplugin_oji.so
/usr/java/jre1.6.0_03/plugin/i386/ns7/libjavaplugin_oji.so
/usr/java/jre1.6.0_03/plugin/i386/ns7-gcc29/libjavaplugin_oji.so
/usr/lib/firefox-2.0.0.12/plugins/libjavaplugin_oji.so
/usr/lib/mozilla/plugins/libjavaplugin_oji.so
The first two lines are the jre installation. The third is a simlink so firefox can find the java plugin. Here is what file shows.
Code:
file /usr/lib/firefox-2.0.0.12/plugins/libjavaplugin_oji.so
/usr/lib/firefox-2.0.0.12/plugins/libjavaplugin_oji.so: symbolic link to `/usr/java/jre1.6.0_03/plugin/i386/ns7/libjavaplugin_oji.so'
For what its worth, the last line is for Konqueror, so it can find java.
Run the commands on your system and see if you get the same or different results. If the symlinks are not correct, you won't get the same ( similar ) list.
Also try launching firefox from a konsole and look for errors when it crashes. Post any errors you can. Possibly we can get a handle on what is going on.