I have found the solution. By looking in " /usr/local/lib/browser_plugins"
I sow that tje file libjavaplugin_oji.so was linked to the "/usr/local/diablo-jre1.5.0/plugin/i386/ns7/libjavaplugin_oji.so", which wasn't working with Konqueror too. So I linked created a new symlink:
[strato@darkstar /usr/local/lib/browser_plugins]$ ls -l
total 2118
lrwxr-xr-x 1 root wheel 60 Jul 6 01:10 libjavaplugin_oji.so -> /usr/local/jdk1.6.0/jre/plugin/i386/ns7/libjavaplugin_oji.so
and it is working fine