In the Fedora version of Squirrelmail if you turn the fortune plugin on to get a quote on the top of your mail folders you may get the following error:
/usr/games/fortune is not found.
This is because Fedora puts fortune in /usr/bin the hardcode path to fortune in squirrelmail is /usr/games/fortune
Find the offending code and edit it
fgrep -R /usr/games/fortune .
./plugins/fortune/setup.php: $fortune_location = '/usr/games/fortune';