On Mac OS X, Flash objects show up correctly if Flash Player 7 is installed and ObjTabs are on OR off. If Flash Player 8 is installed, objects only appear if ObjTabs are OFF.
This definitely needs a fix.
Mac: Flash 8 incompatible with ObjTabs
Should be fixed now in the developer builds:
http://p2.forumforfree.com/1-vt5-adblockplus.html
http://p2.forumforfree.com/1-vt5-adblockplus.html