I'm testing my Android v1.5 app on various Android devices before releasing it. The manifest file is still set to debuggable='true'. I've e-mailed the .apk file to my phone and Kindle Fire and two friends. The app installed seamlessly on my LG phone and also on one of my friend's phone, but it won't install on my Kindle Fire or on the second friend's phone. We've changed the device settings to allow apps from unknown sources, but the Kindle tries to install and then just says, App not installed with no explanation of why. Can anyone tell me how to find out what is causing the problem?

First things first, any device will have to be able to install apps from outside the market to install an app directly. (many devices by default are not set to allow this, or CAN'T be set to without rooting / modification). I am not sure if the Kindle fire can sideload apps (install apps not from the market), that is unless you are rooted. I do have a similar problem on my tablet (hacked Touchpad running ICS), however I get a weird check eclipse crash, which I just haven't been able to investigate.. Note this is from a market version of my app. When sending APKs to test, I make sure they are false on debuggable and fully sign them before testing.

To install on Kindle Fire you would need to edit out the code in the manifest about gps, at the bottom of the manifest file