Hey Mek, I'm not sure about the other guys but I'm pretty sure I speaking for them as well. Its not a new install issue, or a "new to apex" issue. Its a "was working till upgrade issue". Yes I agree that would cause an issue but I dont use a fire wall. My network is a bit to confusing to get in to right now but I can assure you that is not an issue.
If there was some fundamental change to the passive mode that made you suggest that please explain. My guess is you mentioned that as its a common mistake for people to over look. There is something in that last update that certainly is causing issue for some of us.