I’d like to add that the “Latest version available”-function under vBulletin doesn’t work either. TCP IN/OUT for http (port 80) is enabled, and that’s all what is needed according to the vBulletin support staff.
Yes, it seem to be APF-related. I talked with Kevin Stange (from Steadfast) and he suggested that it might’ve been something related to PHP’s “allow_url_fopen”, but that wasn’t the case.
I’ve been seeing some weird error messages too, for example email isn’t always delivered and gives permanent errors when using the APF-firewall + what is described above.