Comment 33 for bug 238629

Could you locate the libjavaplugin_oji.so file ? It should be a symbolic link into the jre i.e.:
$ ls -lah .mozilla/plugins/libjavaplugin_oji.so
lrwxrwxrwx 1 root root 64 2009-03-30 20:27 libjavaplugin_oji.so -> /usr/lib/jvm/java-6-sun/jre/plugin/i386/ns7/libjavaplugin_oji.so