Hi,
make sure that no other webserver is running on port 80 (e.g. IIS if your OS is Windows). You can check if another service is using Port 80 by the command "netstat -an".
You can also define another ip/port by using e.g.
Listen ipaddress:8080
and/or
Port 8080.
Besides that check that the location to the log files points to an existing folder.