New users not receiving activation e-mail

I have a new clean install of Joomla 2.5.6 and CB 1.8.1. When users complete the registration they are greeted with the following error message:

Error loading module MySQL server has gone away SQL=SELECT m.id, m.title, m.module, m.position, m.content, m.showtitle, m.params, mm.menuid FROM sgj_modules AS m LEFT JOIN sgj_modules_menu AS mm ON mm.moduleid = m.id LEFT JOIN sgj_extensions AS e ON e.element = m.module AND e.client_id = m.client_id WHERE m.published = 1 AND e.enabled = 1 AND (m.publish_up = '0000-00-00 00:00:00' OR m.publish_up <= '2012-06-29 03:53:54') AND (m.publish_down = '0000-00-00 00:00:00' OR m.publish_down >= '2012-06-29 03:53:54') AND m.access IN (1,1) AND m.client_id = 0 AND (mm.menuid = 0 OR mm.menuid <= 0) ORDER BY m.position, m.ordering

The user is added to the user table, but no e-mail is being sent to the new user.

We have configured e-mail in the global configuration to use smtp for e-mail, using a configured enterprise gmail address for webmaster@alamedacountyfosterparents.org.

Any ideas how to get past this?
[attachment:1]Alameda County Foster Parent Association-205812.png[/attachment]

looks like issue with your hosting - mysql has gone away.

Not CB related - ask your host for assistance.

I thought the same thing at first, but there are dozens of sites generating the same error hosted across multiple hosts.

This error is only generated upon submissions of new registrations in Community Builder. The database is obviously there and online, as the registrants data is there when you check later.