Apologies for the long delay in responding to this. You really would have gotten an answer sooner if you had posted in the AntiVirus, Firewall and Privacy Products and Protection Methods
forum. We are currently swamped with malware removal requests so posts like this get lost in the shuffle and it doesn't help that an HJT log was not posted.
Those entries are not harmful. They just block some ad servers. If you need more information about Hosts files and some recommended precompiled ones, see The Hosts File and what it can do for you
Have you gained any insight on where this one came from since you posted this? StopZilla may be bundled with some other security app you have installed on your PC, but I'm not aware of any that do that. Are you sure that someone else that had access to your PC in the past didn't install StopZilla at one time?
Best I can do is check your HijackThis log and Uninstall list to see if there is some app resonsible for the insertion of your hosts file. So please post a log and also do the following:
If you still have the New Users Quickstart
screen enabled, click Open Misc Tools Section
If you just have the regular opening screen, click the Config...
button then the Misc Tools
Now click the Open Uninstall Manager
button, then the Save List
button. Save the list somewhere convenient like My Documents and then the list will open in Notepad. Copy and Paste that list into your next reply to this post.