If you mess up your Zenoss permissions you can use the following commands (as root) to restore them:

chown -R zenoss:users /usr/local/zenoss
chown -R root:mysql /usr/local/zenoss/mysql
chown -R mysql:mysql /usr/local/zenoss/mysql/data

chown root:zenoss /usr/local/zenoss/zenoss/bin/zensocket
chmod 04750 /usr/local/zenoss/zenoss/bin/zensocket

Change the paths to suit where Zenoss is actually installed on your system (if necessary).