It's possible the ports needed for gaming in Infrastructure mode (what they call online) are closed and the information for the gaming is being blocked. Try going into your wireless router settings and open these ports in Port Forwarding:
• TCP Ports: 80, 443, 5223, and 10070 - 10080
• UDP Ports: 3478, 3479, 3658, and 10070
Also, out of curiosity, what games have you been trying to play online? Many only have local multiplayer on them (ad hoc) and not actual online play.