There seems to be a problem with the ezslideshare extension. The following blog post should have slides embedded:
http://share.ez.no/blogs/nicolas-pastorino/my-talk-at-international-php-conference-11-today-rest-recommendation-consume-the-right-content-anywhere

This has been surfaced in the extension's forums too:
projects.ez.no/ezslideshare/forum/feedback_ideas_issues/unable_to_get_working