You should be able to find ADE version in menu/Libary/About Digital Editions
Check if you have the same version on PC and on Macbook.
It could well be as I suggested that you have the older version 1.7.2 on PC and buggy new version (2.0) on the Mac.
The .acsm file needs to be handled by ADE, which will convert it to a drm .epub file.
It is the .epub file you must copy to the Kobo.