I ran into the same error 500. But I cannot get to the "add new" area like Patrick can, I can upload the plugin no problem, but as soon as I click "activate", my entire admin crashes and I have to uninstall the plugin via FTP in order to gain access back into my admin area. Here is the error I get:
http://postimg.org/image/wpt0j5jql/
I've tried a different theme and got the same problem.
If this is a different problem than Patrick's, let me know and I'll start a new thread.