Mandatory information about my setup:

Have I searched the tickets before posting? Yes - one ticket #1981, no reply to ticket.
Have I searched the forum before posting? Yes, no results.
Have I read the documentation before posting (which pages?)? Yes, looked at troubleshooting and the plugins, no mention of manage comments section.
Joomla! version: 3.4.3
PHP version: 5.5
MySQL version: 5.0.11 (??)
CComment version: 5.3.3 PRO
Direct link to the page that shows the issue: requires login


Description of my issue:

Cannot access the Manage Comments section. Whenever I try, I get the following error:
Fatal error: Cannot instantiate abstract class ccommentComponentPlugin in {SITE_ADDRESS}/components/com_comment/helpers/utils.php on line 74