Fix prize giving bug

api.lua

@@ -181,14 +181,12 @@ function awards.unlock(name, award)
 	if awdef and awdef.prizes then
 		for i = 1, #awdef.prizes do
 			local itemstack = ItemStack(awdef.prizes[i])
-			if itemstack:is_empty() or not itemstack:is_known() then
-				return
+			if not itemstack:is_empty() then
+				local receiverref = minetest.get_player_by_name(name)
+				if receiverref then
+					receiverref:get_inventory():add_item("main", itemstack)
+				end
 			end
-			local receiverref = core.get_player_by_name(name)
-			if not receiverref then
-				return
-			end
-			receiverref:get_inventory():add_item("main", itemstack)
 		end
 	end