Firstly, check that you have setup an Application ID for your site where you are using Facebook Comments. This Facebook APP ID must be entered in the comments section for any launch/sales/squeeze page where you are using Facebook comments (you can use on APP ID per domain).
Having an incorrect or missing APP ID will normally lead to "href" errors or the Facebook Comments not showing at all
To setup your Facebook APP ID, go to http://www.facebook.com/developer and click "set up new app" and follow the on screen instructions
We have heard of a few issues with the facebook comments API recently. Unfortunately this is outside of our control - we use the correct comments integrate code provided by Facebook so there is no issue there. The problem is coming from Facebook itself .
You can always switch your pages to use WordPress comments if you are worried about the facebook comments reliability - but their system should hopefully be back up and running fully soon.