Incompatibility between e-Newsletter and Easy Pricing Tables

When using e-Newsletter, I see this error message when opening the newsletter "new newsletter" screen:

Fatal error: Call to undefined function get_current_screen() in /home/ilovedan/public_html/wp-content/plugins/easy-pricing-tables/includes/post-types.php on line 267

...instead of showing the template I have chosen.

The error only shows up when I open the new newsletter screen.