Was it after you updated that LW stopped connecting, or did you update because the old version had stopped connecting?

Try removing all of the LW rules from McAfee's config & start from scratch. Also, double check that the Windows firewall is off. If that doesn't help, check the thread below for more fixes to try.
If LW Will Not Connect

What's the model of your Linksys (if it's not showing on top, have a look underneath the router)?

Where are you connecting from (house, apartment, work, school, dorm)?