You are rigth both of you. I forgot the '00' before 'C018'. My 'Program Change' line is placed correctly just befor the melody is played.
But trying to figure out how the MIDI file is structured, and get som expirience by trial and error, is funny but also hard with a steep learning curve.
Being a digital interpreter it is not surpricing that MIDI system want its files composed in correct order. Sometimes I get a little dizzy.
I guess that was why the zeros disappeared.
Thank you for your help! I will return soon I guess