hi guys. I'm Sylvain who solved the thing, thanks for relaying the info here! :) The blog indeed crashed, it's on a very small VM with a remote filesystem and even with a WP cache plugin.. not so much luck, even with apache stopped. However our company blog has a proper sysadmin ;-) So after I setup a redirect there no more issues... until we get on slashdot maybe ? :) Cheers!
From the screenshot of the form you got after solving the equation, it looks like you need to have a U.S. address to receive the Cr-48, and it would appears poor you're located in Paris/Luxembourg. You need someone to forward it on to you? ;)
generally speaking, it's extremely frustrating for an european startup to see these regular U.S. only launches from Google. (come to mind Google Voice, ebookstore, google music, and now Cr-48...) But well, small price to pay to enjoy living in Paris most of the time :)