Mailchimp integration - error after installing

Hello, Just got this code after installing "Mailchimp integration" and clicking "settings" to configure it:

Fatal error: Cannot redeclare class Mailchimp_Folders in /home/motivaca/public_html/wp-content/plugins/mailchimp-sync/mailchimp-api/Mailchimp/Folders.php on line 3

NOTE: I was using "MailChimp for WordPress Lite" pluggin before.