Well, using supporter + advertising last version, on several farm pack themes I still have the display bug :
(test blog for testing buddypress groupblog.)
Before post ads are DEACTIVATED
Only have after post/before and after page.
As you can see the ad code displays directly AFTER the "test" text (post content).
WP 3.0.2 / BP 1.2.6 supporter and advertising last versions