Seems to me that either the MySQL server is down, or the mysql.sock file is missing. If the server is down, you can start it by typing this:
/etc/rc.d/init.d/mysqld start
..depending on your system's configuration, that may or may not start the daemon.
Also check if the sock file that its looking for is actually there. To do so, type this:
ls /tmp/mysql.sock
..if its there, it'll spit that filename back out to you. If it isn't, it'll say "no such file or directory." If you see the latter, you'll need to find it and create a symlink to it. To find it, type this:
locate mysql.sock
..and it'll spit out the files true location. Then type this to create a symlink:
ln -s /true/location /tmp/mysql.sock
..Hope this helps.
P.S. YOU HAVE TO BE ROOT TO DO ANY OF THIS. IF YOU'RE NOT, COMPLAIN TO WHOEVER IS.