Same issue and after weeks of pointless emails with there tech support I am still no closer to getting a game in!
One interesting bit of info did come out of it though:
our developers are currently aware of this problem and are trying to solve it.
Please make sure one more time that you have your camera shake disabled:
go to Configure -> Game ->Difficulty -> and disable Camera Shake
Please note that on some servers this could be forced by the server settings.
This would imply that the issue is related to head bob/cam shake? so why can't a hot fix patch be released that disables this function client/server side?
anyone with this problem should email tech support to get the pressure on and get a fix out!