Member pages of Buddypress aren't working anymor after update from 1.1.3 to 1.2.3.

I've noticed that the member pages aren't working after an update from BP 1.1.3 to 1.2.3.

I've used the backward compability plugin, disabled all plugins and added Buddypress Social 1.1.8.
Does anybody know a solution?

Also, where is the 'Blog' page of the Social theme? When I type '/blog' after the domain that page isn't working anymore also.