Wireless internet is not a problem as long as its stable normally...and it would never make a game crash at the same spot etc.
A firewall could cause problems, but I doubt that is the case since I would guess it already had given Kaillera access to internet through the right ports, or else you wouldn't even be able to log on a server.
My guess would be that the problem lies elsewhere...tried other emus with net capabilities? If you get the same problem there it could be something firewall related, or at least Kaillera related. Hope this was of some use...