Out of the blue, an Apache 2.2 server suddenly quit accepting traffic on port 80. The error message was "An attempt was made to access a socket in a way forbidden by its acces s permissions could not bind to address 0.0.0.0:80 ". It took a while, but the server is now back up. See the details on the solution at http://dvdsdirect.us/notesapacheforbidden80.jsp
Try restarting apache, or using ps aux | grep httpd to find out if it's still running. If so, kill the pid.