If you have issues on your registration page with DJ-Classifieds with such error: 

Warning Field required: Terms of Service

Go to: Extensions -> Plugins, search for User - Profile plugin and click to edit it

Once editing the plugin make the "Terms of Service" setting to "Disabled"

and Save the plugin.

(It's needed as the DJ-Classifieds registration uses the same core Joomla! registration mechanism which is checking if the required fields set in this plugin are present).
Learn more about DJ-Classifieds registration plugin.