Fail to install APK in android 2.2

Unity Engine
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1

Hi ,

I am developing a game with unity 4.1.3f3 for PC and Android platform .

Recently with the unity free mobile publishing , i can publish my game to mobile devices … so here is the problem :

I bulid android platform with SDK platform Android 2.2, API 8, revision 3
but i can not install the APK run in my android simulator
and i get this : " Failure install failed invalid apk "

but , there is no problem when i build with Android 4.0 , API 14 …

How can i fix that ???

2

maybe the same Problem like this
http://forum.unity3d.com/threads/183895-Apk-file-doesn-t-run-my-android-device

Edit: sorry dont saw that is working with Android 4.0 :-/