Check Wowza log for bind errors. Be sure don't have web server on port 80. Be sure tcp port 80 is open and properly mapped to Wowza server ip address. You can test connectivity on port 80 by opening web browser and entering following URL, should show wowza server version number:
Check the Wowza Media Server logs and see if there are bind errors ([install-dir]/logs). If there is a port conflict you will see ERROR log statements every few seconds saying it cannot bind to port 80.