Jetpack broken

I needed to create another wordpress blog and now the jetpack install but can not open. Once installed, I click the jetpack and me back a 500 error. Opens only the omnibox. In the previous blog with old version worked usually remains and also other professional blog that I maintain it runs smoothly.

Already uninstalled, deleted the folder, installed again and nothing … Where can I download old versions and try to solve? otherwise I will have to uninstall

http://wordpress.org/plugins/jetpack/