First of all, be sure to have at least v7.013 (or bundle version 1.045)
Be sure to have properly updated the plugin (through auto-updater or deleting/installing it).
This new version brings an important database update and because of this, in the changelog a full database backup was strongly suggested.
If you still have issues, try going in your WP admin and use this URL: http://YOUR-WEBSITE/wp-admin/index.php?pc_update_db_v7&pc_php_debug
Is a manual trigger to update passwords in the database. If you didn’t see any strange message, you should be ok.
IMPORTANT: if you have Mail Actions add-on, be sure to have at least v1.7