OK so I hate firefox ugly icon that arch uses the head of a dinosaur and I wanted a newer version of firefox because 1.0.4 is old. So any ways I go uninstall firefox via pacman and download the firefox installer. I install it it to /usr/local/firefox. I installed else were a while ago and had the same issue. The clock applet wouldn't load and I got The panel encountered a problem while loading "OAFIID:GNOME_ClockApplet". How can I fix this.
"The only thing we have to fear is fear itself." - Franklin D. Roosevelt
You could try mozilla-firefox 1.0.6-2 which is in testing repo. I don't know if it has stability/usability issues. Maybe it uses another icon.
pacman -S nss-nspr and your problems will be solved instantly