Problem with feed - new items not importing

Hello,
we are having a problem with a feed in the autoblog plugin. The items in the feed are not importing. If we test the import this is the response:
"Reached an already imported entry so stopped processing the feed"
Only the first item gets imported, the newer ones are ignored..

This is the feed url:
http://pzd.klantsite.net/l/nl/pzd/export/urn%3Auuid%3A79e1816f-4f17-4b72-88b5-21efde051f3e

the feed is valid and shows up ok in other feed readers fe. http://cloud.feedly.com/#subscription%2Ffeed%2Fhttp%3A%2F%2Fpzd.klantsite.net%2Fl%2Fnl%2Fpzd%2Fexport%2Furn%3Auuid%3A79e1816f-4f17-4b72-88b5-21efde051f3e