We don't have a set fix for this because a 500 error is server side error and generally doesn't have anything to do with the plugin itself. However, I can recommend a couple things that have worked in the past when people have brought up this issue, but these solutions don't necessarily work every time.
First option would be to check for conflicting plugins. This shouldn't be an issue since the problem is server side but occasionally this has resolved this problem.
Another option would be to delete your browser cookies and clear your browser cache.
If these work for you, then please let us know. Also, if you find conflicting plugins please give us a name. We are working on putting together a list that we can present to help with troubleshooting.