I get the error, if I send the zipfile and open the AIMMS File which weirdly has only 1 KB, the main project doesn’t exist… please help me solve this hell task  

I get the same error if I try to open an .aimms file in a compressed folder. I think the problem is that you should first unpack the folder again before you can open the model.

What happens if you open a file directly from a zipfile, is that Windows will unpack that file to a temporary location and will open that file. When AIMMS opens such a temporarily unpacked .aimms file, it also wants to open additional files from the MainProject folder. These are not unpacked by Windows, however, hence opening an AIMMS project directly from a zip file will fail. 

So, I think the error here is that direct access to zip files in Windows Explorer give a false sense that all files in the zip file will be directly accessible, which they are not, unless you unpack the zip file.