This pkgs were compiled against VL 4 download edition. XFree86-4.3.0, and 
kernel 2.4.22-scsi.

You should remove any pkgs of the same name before installing these.  This firefox was compiled against this set of packages.  Earlier versions will not provide the dependancies required.

You should put pkgconfig.sh into /etc/profile.d and make sure it is executable;
ie, chmod 755.  And reboot for it to take affect.

You should edit /etc/ld.so.conf and add the line
/opt/firefox-0.8/lib/mozilla-1.6

Run ldconfig

If you had Firefox installed before make sure to remove $HOME/.phoenix and possibly .mozilla

Let me know if you have any issues

Inggy