Great discussion and help btw from you all.
I have the issue that it works on my end and all my DAWs perfectly when exported, but not on other PCs which sseems like not a GLSL issue but more like a "stoored in plugin issue" I guess?
@Christoph-Hart mentioned the "File -> Copy embedded files to project folder" method which is not avaiable in the current HISE version. I got the glsl script in my project folder in the Scripts folder but it seems that's not right?