Hi Melina,
Thanks for letting me know – and sorry for your bad experience.
This is a well known issue AP has with a few older graphics cards on PC. I am not able to do something about it right now, but we will hopefully have found out what exactly is causing this and have done a fix for it – with one of the next alpha releases.
If you have access to another computer, you can try Animation Paper there – if that is at all an option for you of course. In the meantime we will work on fixing it.
Thanks,
Niels