DJ-Catalog2 - com_djcatalog2 (Pro feature)
Go to your Joomla backend -> components -> CComment ->settings -> new, from the component dropdown field select com_djcatalog2 and click next. Save the configuration.
Now go to Extensions -> Plug-in Manager and find the DJCatalog2 - CComment plugin. Enable it. Now in single view of a djcatalog2 item you should see the comment form.