When selecting pixels, you may receive the following message from the script:
Lost connection to MySQL server during query
Dear Webmaster: The current MySQL user does not have permission to lock tables. Please give this user permission to lock tables, or turn off locking in the admin
Your hosting account does not support table locking. Please go to your admin section and turn off table locking in Main Config (see MySQL settings).
Another (more advanced) option is to give locking permissions to the database user. This can be done using your web host's account management features. Some hosts do not support this option, for example a GoDaddy account will not let you do this.