BuddyPress.org

The activity streams issue is related to bp 1.0.1 other people seem to be having a similar problem with that verison of bp.

If you are using bp 1.0.1 then you need to be using bpc alpha 2.1 which is here:

http://ourcommoninterest.org/downloads/bpcontents10a21.zip

The alpha 2 version will not work properly with bp 1.0.1.