The file jcomments-v2.1.js filters out the hostname and resets it to location.hostname when there's a difference. Location.hostname doesn't come with the port number (firefox 3.5.7) so the port number is removed. This means that no new commands are received by the server (probably also no edits etc, didn't test that).
A small fix could resolve it. Maybe the JoomlaTune team can take it in their next update.
See my post on
http://www.joomlatune.com/forum/index.php/topic,1071.msg4067.html#msg4067.
Wo.