I'm relatively new to Android and am trying to give Avast! Anti-Theft the ability to download non-Market apps in my Samsung GS2 (GT-I9100T), running ICS 4.0.3. Avast! Anti-Theft tells me to "Please enable installation of Non-Market apps in your system settings." However, when I go into my Settings and click on Applications, I don't have an option to download non-market apps. So far as I can tell, the choice to enable non-Market apps doesn't exist in my phone. Have I missed it? If anyone can tell me where to find that option and how to activate it, or if that option just isn't available to me, I'd be most grateful. Thanks.