BuddyPress.org

I have resolved this problem if anyone else is having it:

These two lones were not correct at the top of bpdev-xml-rpc-classes.php, make sure it looks like this and you should be fine!

require_once( ‘/yourpath/wp-includes/class-IXR.php’ );

require_once( ‘/yourpath/wp-includes/plugin.php’ );

Now I can really get stuck in to the iPhone app, yay!