It seems there is a service using this port. You could kill it by executing:
sudo kill -9 $(sudo lsof -t -i:80)
Then, try to start Apache again.
I ended up doing the following to get this to work:
In /opt/bitnami/apache2/conf/httpd.conf, change the following lines:
Seems to work for me.
UPDATE mdl_user SET lang='pt_br' WHERE lang='en'