Go to Admin > Awards > Attendance Awards and examine carefully all rows (you may need to scroll down) in the grid under both Club and Sunday School/Church tabs. For any rows that have the "Include" column checkbox checked, there needs to be a valid Award Name and Award Item Number listed. (The Grade, Term, and Absences Allowed Per Term need to be filled in too of course.)
[Note: in the Windows app, the Awards tab is under Admin > System Settings.]