[Plugin: WordPress Form Manager] Data Submission Download Error

Urgent pkease help. I get this error “Fatal error: Call to a member function initValidators() on a non-object in /home/petracco/public_html/wp-content/plugins/wordpress-form-manager/settings.php on line 24” when i try to download the data of any of the forms created. Please help

http://ww.wp.xz.cn/extend/plugins/wordpress-form-manager/