Try the tips here:
If LW Will Not Connect
Make sure that your XP firewall is properly off & that the Trend Micro firewall's allowing LW. You might have to remove the current LW rules, then start from scratch & add them again:
PortForward.com - Free Help Setting up Your Router or Firewall
Otherwise, try port forwarding for your 2wire:
Port Forwarding for the 2 Wire 2701HG-G