On Access Scanning is part of McAfee's VirusScan. Do you also have a McAfee firewall?? If so, you need to make sure that you're only running one software firewall (more than one will cause problems) & that firewall's configured to allow LW. Check the link below for info about configuring McAfee's firewall.
Port Forwarding for the McAfee Security Center

If that doesn't help, please give us your details: System details - help us to help you -> Provide these details when you post!!!

And also check this link for connection fixes: If LW Will Not Connect