Failed to restart Apache while installing mod_pagespeed

I was trying to install mod_pagespeed, after installing when I tried to restart Apache, I am getting this error:

[root@webuzo ~]# /etc/init.d/httpd restart
Stopping httpd:                                            [FAILED]
Starting httpd: httpd: apr_sockaddr_info_get() failed for webuzo
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
(98)Address already in use: make_sock: could not bind to address [::]:80
(98)Address already in use: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs
                                                           [FAILED]