I just downloaded the zip file and tried on my test ePO server running 5.3.1. Had no issues with installing into our master repository. Maybe the package got corrupt when you downloaded it via your grant number. That has happened to me in the past. You may want to try downloading it again.
I tried again and now it works. But with the same package. I saw that the master repository didn't update last night so I restarted the server. Then it worked. Thank you anyway!