Re: messaging error
There have been various messaging bug fixes to RC1 since it was packaged. Either you should upgrade to the newest trunk (read this thread: https://buddypress.org/forums/topic.php?id=2171 then this thread: https://buddypress.org/forums/topic.php?id=1994 ) or wait for a packaged zip of RC2.
Remember, BuddyPress has not yet been officially released as version 1.0. This means that it is a work in progress and changes are literally being made to it everyday. Running it in a production environment is strongly discouraged until it is officially released.