A 500 Internal Server Error is like the check engine light on your car. It says something is wrong but not exactly what or where. Without the details of that log entry, I could not tell what went wrong. However, more likely than not with these auto-upgrader items is it is something in the extraction of the files. The log entry will tell you for sure where the issue is. Again, if it is an issue with the software, we will certainly assist you but if it is an issue with your server, we will need to move this to the advanced self-hosting support forum for peer to peer assistance as that is outside our scope of support.