Re: Registration is not working
Switch to the default BuddyPress themes and deactivate all plugins except BuddyPress. Try the registration process again. If it works, switch to the FaceBuddy theme. Try registration again. If it is still working, activate one of the plugins, etcetera.
You must distill your BP environment down to the lowest common denominator–default themes, no plugins except BudddyPress activated–and see if everything works with that set up. If so, you then add one thing back at a time (first your custom theme, then one plugin at a time) until the problem occurs again.
Let us know what you discover.