Little Adobe Plugin Fix
I found that the Adobe PDF plugin for Firefox wasn’t working, so I ran Firefox via the console to see the output. The plugin was complaining about not be able to find the XtCalloc symbol. I guessed this would be in libXt.so, so a quick test with LD_PRELOAD=/usr/lib/libXt.so made the thing work, whoopee!
To fix it all the time, just edit your /usr/bin/firefox script to include the line:
LD_PRELOAD=/usr/lib/libXt.so
somewhere near the beginning.