Getting an Error on Account Has Been Activated Page


I am getting the following error on the Account Has Been Activated Page:

Warning: Missing argument 1 for FPD_Install::activate_plugin(), called in /home/sitesteam/public_html/wp-content/plugins/fancy-product-designer/inc/class-install.php on line 42 and defined in /home/sitesteam/public_html/wp-content/plugins/fancy-product-designer/inc/class-install.php on line 48

The account and site is created and everything works as it is supposed to.

The signup page is

Please let me know how to correct this.