no its all okay
Potentially so yes, as if you recall what I mentioned about such:-
didnt you say keeping the hosts unchanged was dangerous and strongly advised against doing so?
Though is some rare instances such as with your machine it will not play nice so to speak and can affect normal browsing operations. You can always replace the default again but do bare in mind your machine is not exactly unprotected whilst used online because you do have avast! Internet Security installed. Plus using McAfee SiteAdvisor etc, though you may wish to consider using Web of Trust instead of the aforementioned as I have found it to be both more effective and accurate at times.
A Hosts file is like a phone book. You look up someone's name in the phone book before calling him/her. Similarly, your computer will look up the website's IP address before you can view the website.
Hosts file will replace your current Hosts file with another one containing well-known advertisement sites, spyware sites and other bad sites. This new Hosts file will protect you by re-directing these bad sites to 127.0.0.1.