The root password for the mysql database in the Virtual Machines or AMIs is "bitnami". The error that you are getting is that the 80 port is not free, another server or application is using it. Try to stop another application and start it again:
$ sudo /opt/bitnami/ctlscript.sh restart apache
You can check other servers that they could be using this port:
$ ps aux | grep http
You can copy your sites and publish them in "/opt/bitnami/apache2/htdocs" folder.