Can someone help me fix the Error ?

For your future projects...don't use premade behaviors. Learn how to make your own.

I don't know what to give you both cuz i don't have money. but i will still gonna study more and understand the logic so that in the future i might can help too. thank you very much to both of you and other users who tried to help me too.

That will be enough Without the pressure of your thesis, you will surely be able to reflect more on your code and improve

Yeah this thesis do really give me pressure and I can't think well when thinking about the deadline.  If got more time i'll study because in my school, we never learn to code or to make games.  We only know how to develop a system using php. Anyways thank you very much for your help.  I may not understand all these logics on the behaviors but I do understand simple logics now. and will improve it in the future .