Problem with Thumbnail display

Hi,

I have a problem with the proper display of the thumbnails. Unfortunately only the default thumbnail is displayed.
As an example, please take a look the bottom of the page http://www.finanztreff.org/optionfair.
As far as I remember, the thumbnails have been properly displayed until the last plugin update, or so.

I tried reindexing but the images don’t show up anymore. Any help is highly appreciated!

Thanks

http://wordpress.org/plugins/nrelate-related-content/