Try this:
1 - In setting of your Android device go to security and make sure Unknown Sources is ticked.
2 - If you have the MIT Companion App installed you need to unistall this first then install the MrAI Companion app.
Donation are always appreciated as I spend most of my spare time developing AI, but no there is no obligation to make a donate as I am currently keeping the service free to use while it is in the Alpha stage. I am not far a way for releasing the next Alpha versions which has new components and an enhanced interface over the MIT version(As seen in my videos). In the next release I've made it easier to see the component I have modified The new and modified components all start with the letters mr (e.g. mrSoundRecorder, mrAllinOne, mrSlider, mrSound, mrSphero etc.) Also you will be able to import MIT created App Inventor projects in to the Mad Robots AI
Just remember when using the Mad Robot AI it's a test version and currently you won't be able to package a final APK (This feature will be available eventally).
Hope this helps
Gareth