I can't access this site now:
Something on your site is broken and tries to save the plugin state in the cache. This is a major security issue and will cause your site to not work properly. Go to your site's backend, Global Configuration and set Caching to OFF as a temporary solution. Possible causes: older versions of JoomlaShine templates, JomSocial, BetterPreview and other third party Joomla! extensions.