Hello, everyone. I have decided to make this thread in order to teach you all how to fix the issues in question. Make sure to check this thread out thoroughly.

Fix For The Flash Player And Black Screen Problems:
- Open IE, (Internet Explorer)*.
- Download the most recent version of Adobe Flash Player.
- Install it.

You are done. Now, you will be able to open any trainer without any problem.

*The use of Internet Explorer is very important. You should not use the well known browser called Google Chrome since although it keeps its own Adoble Flash Player version up-to-date automatically, it doesn't actually update your computer Adobe Flash Player version accordingly, which is the one that matters.

Fix For The "Authenticating Account Info..." Problem:
This is a temporary problem which often happens when you download a trainer for the first time. Just wait a little while and it will fix by itself.

Hope you guys have found this little guide of mine useful.