It looks like some plugin removes some words from page. Because instead code:
<script src="/components/com_jcomments/libraries/joomlatune/ajax.js?v=4" type="text/javascript"></script>
we have
<script src="/components/com_jcomments/libraries/une/ajax.js?v=4" type="text/javascript"></script>
as you see we've missed 'joomlat' in the path to JComments's script... I do not know why - you have to find who removes this text.