Using featured image isn't working and there's no errors or alternative ways to deal with

So I installed the plugin and set it up. Ticked the add-on "use featured image". It adds the post (also not sure about author, doesn't end up as a meta) correctly except the image.
This is taken from the feed:

<author>Martina Shabonet</author>
<description>#Uppdrag1 #thisisorebro</description>
<pubDate>Thu, 10 Jan 2013 13:02:22 GMT</pubDate>

Here are the settings:

What do I need to do to make it work? Also I'd like some input on the <author> tag, as is it's a name and it doesn't show in a custom field either.

Best regards,