I'm unable to see the 'refresh' issue. If there's some way to recreate that, let me know. When I go to your page, if I hit "Connect with FB", it logs me in, remains on the same page (with the invite module) and it loads as expected.
As for the 5 columns, I don't have much good news to tell you. According to their documentation, 5 cols should work. Technically, there's not even an option for 4. However, in their demo picture, and in our testing, we can get the 5 col option to work either, it sets it to 4. We'll keep testing, but there isn't a way to override this, we're at the hands of Facebook on this one. If we figure something out, we'll definitely update the module and post back here.
Documentation of the friend selector. Specifically, look at the 'cols' definition:
wiki.developers.facebook.com/index.php/Fb:multi-friend-selector