I'm not the lead developer so don't know as much, but your Joomla template might be conflicting... that PHP warning actually outputs to the COMMENT box!?!?
That's very strange...
Try doing it again with the 'modern' template of JoComment. If that doesn't fix it, i'm not too sure... hopefully Daniel can get on soon to track it down - it might be a bug.
EDIT: I'm also seeing at the top of the article view the following error now -
Notice: Undefined offset: 2 in /home/pillar3400/public_html/plugins/content/slideshare15.php on line 82
...it may be an problem with the site that's unrelated to JoComment