Assuming you are Windows, this must be a glitch with reading .zip files made on a mac. I'll have a look for another app to do compression rather than the default MacOSX app. They are still there without an issue here. Which size do you want I'll send it to you?
I have no idea, I think windows just doesn't like the way mac compresses files. I have no idea how to diagnose. I don't share them in 1920x1200, but 16:10 for your aspect ratio. [link]