Can't log into Facebook

Hi all! I just got a new MacBook Pro with Retina display yesterday. This is my first Mac as I've always been a PC user and so I am slowly finding my way around the various bottle necks that I encounter. In time I shall over come them but in the meanwhile I guess I shall be posting a lot of queries here for others to help me out. Now I would like to ask a small (may sound trivial to some) question about logging in into Facebook. I went to 'Settings' -> 'Mail, Contacts & Calendars'. I had setup my email accounts and Twitter earlier but once the system updated the OS to 10.8.2, everytime I come to setup another account it just does not respond. I can't setup any addition accounts, leave alone Facebook. Can someone please help me with this? Thanks in advance!