Thank you sir for providing the solutions. It eventually worked.
I had some troubles with engaging the Action Replay menu. Everytime I loaded up a game (could be any game) it gave me this message below.
It seemed I downloaded the wrong .3gx file. It was smaller then the correct file. The correct .3gx file is
651kb big and is called
CTRPluginFramework.3gx. After renaming this file to
default.3gx the error message was gone and I could open the action reply menu (by pressing SELECT) and CTRPluginFramework 0.6.0 was shown.
Sidenote: Even with the incorrect .3gx file it still gave me a short blue flash screen when booting a game and if a .3gx plug-in was correct I did manage to select the action replay menu. < For those who are struggling.
Thanks
@Nutez for your help and explanation.