i'd say you're right in that those two messages on their own are not a problem - its just that apache is listening on a port with no vhosts. There are lots of notes around about resolving that but on its own not a problem.
Are you saying that httpd fails to start altogether? Are you saying you cannot see httpd in a process list or access any of the sites?
You don't say what OS you're running, have a look in the log files see if there's any errors. This could be /var/log/httpd/error.log or similar.
You might try "httpd -D FOREGROUND" see if it spits out any errors there as well?