script inside script execution order

I have a poblem and it would be very nice if someone could help me..

I am building an inventory system, with help of a youtube video. In this video the youtuber takes the scripts and he has no problems to pull them inside the script execution order. I have the problem, that i cant pull my item script inside, because he gives me an error and thiss cript isn't listed inside the list of scripts.

I watched every letter 10 times and i haven't made mistakes.

It is a c# script.

Can u help me ?? Can it be a problem with the script ??

I hope u can help me find a solution. Wargrott