Error on Donation checkout page

This warning appears on the donation checkout page.

warning: array_filter() [function.array-filter]: The second argument, 'ec_recurring_filter_recurring_products', should be a valid callback in /sites/all/modules/ec_donate/ec_donate.module on line 155.

warning: Invalid argument supplied for foreach() in /sites/all/modules/ec_donate/ec_donate.module on line 156.

Any ideas? I'd love to be able to use this module.