My Facebook connect stopped working on TopTopGames.com for some reason. I have no idea why. Try contacting Facebook support and they practically did nothing for me.
Since this issue, i tried to use Facebook code from the documentation on both sites (toptopgames.com, flashgratuit.com): https://developers.facebook.com/docs/guides/web/
Here are the test files:
http://toptopgames.com/test.php
http://flashgratuit.com/test.php
Only changes are the name. I tried playing with the code. Downright copying and paste the developers document ion code. I tried making new API keys. None of it worked for TopTopGames. I copied the script over to other sites and it worked fine.
Just a guess: https://developers.facebook.com/bugs/306864219353317?browse=search_4ef1c2c9d79587d72785127