I have a clean install of MySQL (mysql-5.5.24-osx10.6-x86_64). I am on Lion (OS 10.7.4) with a Mac Pro Quad Core. I installed MySQL the GUI installer and also installed the
In /usr/local/var/mysql I found a file in the form COMPUTER-NAME.local.err. Simply changing that file name solved the problem. I could now start the mysql server with