ln mozilla /usr/bin is not a symbolic link, but a hard link. In this case the link isn't followed, but it is like a copy of mozilla, but without wasting hd-space on it.
The command you need is
$> ln -s /usr/local/mozilla/mozilla /usr/bin/
did you copy /usr/local/java/jre<version>/plugin/i386/ns610-gcc32/* instead of /usr/local/java/jre<version>/plugin/i386/ns610/* to your plugin directory. This is an often made mistake.