XP SP2 reduces simultaneous connections. A patch can fix it. http://mitglied.lycos.de/lvllord/download-mirror.htm
However, a recent M$ update has caused a lot of people problems & still is. Check your OS settings & registry changes. The M$ update might have reset or changed some of your settings. Also recheck your firewall.
Configure your firewall so it allows LW full access (advisable not to have 2 active firewalls b/c they can interfere with each other); Firewall configuration instructions (click on link)