[Plugin: Visual Form Builder] VFB Pro error in "Edit Form" view

I just bought and installed the pro version of the plugin. Unfortunately, it appears to be a bit broken for me.

It imported my previous forms and most of it seems to work, but I can’t edit the form. It creates a php error.

PHP Fatal error: Call to undefined method WP_Screen::get_columns() in /Users/dd/Sites/wordpress/wp-content/plugins/visual-form-builder-pro/includes/admin-form-creator.php on line 49, referer: http://wordpress.localhost/wp-admin/admin.php?page=visual-form-builder-pro&action=ignore_notice

My screen looks like this: http://i.imgur.com/fgD6Y.png

Please help

http://ww.wp.xz.cn/extend/plugins/visual-form-builder/