This article describes the issue of the "For security, your phone is set to block installation of applications not obtained from the Android Market" error message being generated, when a user attempts to install Smarterping - tracker application on their android device.
Issue or Goal
Many Android device owners would like to install applications that are not located within the Android Marketplace. If a user attempts to install a non-market app onto their android device, the "For security, your phone is set to block installation of applications not obtained from the Android Market" error message is generated; if unknown sources is not selected on their Android device.
Who are these Unknown sources and what do they want? In simple terms, it is anything other than the Android Market; it could be an app sent by e-mail or downloaded from a website.
If you're worried about the security implications of allowing unknown sources, there's an easy fix - install the app from outside the Android Market and then select the checkbox again to turn them back off.
Users, who are trying to install non-android market applications to their device, will receive this error if the unknown sources option is not selected.
1. To allow Smarterping apps to install, tap the menu button on your home screen and then select
2. Scroll down the list and tap Security, then on the right, scroll down and tap Unknown sources.
3. Tap OK on the prompt that appears.