If that Happens Make Sure The Masking Name Has No Characters Such As ('!@#$%^&*()<>") For Example, Also Make Sure Its A ".png" file And That You Type In The Full Name Too Such As "MyMask.png" And When You Are Making The Mask The Colors Should Be "RBG Red, RBG Green, RBG Blue, RBG Purple, RBG Yellow"
Also Make Sure the Mask Is Sized Either 513x513