How do I give mysqld write access to a directory?
Depending on the uid mysqld is using, chmod 700 on the data directory might not help. You may do the following:


chmod 777 /usr/local/mysql-5.5.15-osx10.6-x86_64/data/
Startup mysqld again
ls -l /usr/local/mysql-5.5.15-osx10.6-x86_64/data/ to identify the owner of the created files
chown OWNER /usr/local/mysql-5.5.15-osx10.6-x86_64/data
chmod 700 /usr/local/mysql-5.5.15-osx10.6-x86_64/data/