Installing the wysija plugin completely broke my Admin-panel resulting in nothing else than a 500 internal server error when trying to access the WP Dashboard. The site itself was still accessible though, only admin was broken.
Disabling the plugin manually in the MySQL table fixed the issue. I tried re-installing and activating again, same issues.
Running WordPress 3.3.2, dutch localized version. Active other plugins:
Akismet
Buddypress
bbPress
Buddypress template pack
Exclude Pages from Navigation
Jetpack by WordPress.com
Lightbox Gallery
SEO WordPress
SI Captcha Anti-Spam
Watermark my image
Wordpress Importer
Everything is updated to the latest versions.