On Solaris8 (Sparc/IA) , RedHatLinux6.2J with firefly.
ControlPanel.html can not launch with browser pr3,
launch ControlPanel with console is no problem except redhat linux
(see also 4375804).

If open the ControlPanel.html with pr3 the message displays below.

"Netscape cannot find the Plugin Downloader Plugin.
Without the Plugin Downloader Plugin, you cannot automatically download
and install plugins. Please visit http://www.netscape.com/ to install
the Plugin Downloader Plugin."

Tested firefly binaries are
 /usr/local/java/jdk1.3.0_01-beta_refresh-2/bundles/solsparc
/solx86
/linux
Tested pr3 binaries are
/net/oxe.east/files/files1/n6/pr3/solaris
                                 /linux


Reproduce to:
1. Launch mozilla with jdk1.3.0_01-beta plugin enabled.
2. Open ControlPanel.html in $JAVAHOME