Invalid APK file while loading default app

Issue

I wanted to try to make an Android app, so i downloaded the entire dev pack. Everything seems to work fine, but when i try to launch the app (i haven't modified anything, it just has the default code in it) on my Galaxy S3 with 4.1.1, it tells me that there is an invalid apk file... I tried it on an emulator, it stopped with a black screen and didnt get further than this in the console:

[2013-05-01 21:27:06 - MyFirstApp] Waiting for HOME ('android.process.acore') to be launched...

Did i do something wrong, or is something missing? Thanks in advance.

Solution

I think you can use this questions answer. Seems similar to your problem. Hope this helps.

Answered By - ACengiz