Broken permalinks

Hi there,

After the WordcampEU meeting last year I wanted to use babble for a multilanguage site.
So I set up a test-site: rwl.uitproberen.eu

It's a dutch website for a farrier, which I would like to translate in English (and German).
So I downloaded babble and an English language pack.
The links in the main menu worked untill I activated Babble for the first time.
Now, when I click on a menu item I get a 404 warning. This happens with every link

I tried deactivating Babble, changing permalink settings... I keep getting the 404

The theme I'm using is Foxy from Elegant themes.
I'm usinbg the following plugins:
- Akismet
-WooCommerce
-Wordpress SEO (Joost de Valk)
(-Babble)
(- Babble: translation group tool)

Start by reproducing the 404s on the reported site after activating Babble, using its main-menu links and permalink settings. Compare behavior with Babble disabled and account for the listed Foxy theme and plugins; done means menu links resolve correctly for the multilingual site without 404 responses.

Written by the indexing model from the issue text.