diff --git a/app/controllers/user_admin_controller.rb b/app/controllers/user_admin_controller.rb
--- a/app/controllers/user_admin_controller.rb
+++ b/app/controllers/user_admin_controller.rb
@@ -142,7 +142,7 @@
       ustat[0] = u
       @problems.each do |p|
         sub = Submission.find_last_by_user_and_problem(u.id,p.id)
-        if (sub!=nil) and (sub.points!=nil) 
+        if (sub!=nil) and (sub.points!=nil) and p and p.full_score
           ustat << [(sub.points.to_f*100/p.full_score).round, (sub.points>=p.full_score)]
         else
           ustat << [0,false]