Hi Martin, I'll remove your skybox texture kindly, and will remove you from the credits. My only intention was to help other people with their own development of 3D GameMaker games for educational, personal and commercial use.
Please allow up to a week or so for me to release an update, as I've got a day job and family. Then I will remove your skybox textures, I do apologise if I have caused you any inconvenience.
Regards,
TeamCS1