diff --git a/std-script/grade b/std-script/grade
--- a/std-script/grade
+++ b/std-script/grade
@@ -56,9 +56,15 @@
     else
       result_file = File.new(result_file_name, "r")
       result_file_lines = result_file.readlines
-      run_score = run_score + result_file_lines[1].to_i
-      run_comment += result_file_lines[0]
-      run_comment_short += char_comment(result_file_lines[0])
+      if result_file_lines.length>=2
+        run_score = run_score + result_file_lines[1].to_i
+        run_comment += result_file_lines[0]
+        run_comment_short += char_comment(result_file_lines[0])
+      else
+        run_comment += "result file for test #{test_num} error\n"
+        run_comment_short += RUN_ERROR_MARK
+        log "Error in #{test_num}/result!"
+      end
       result_file.close
     end
   end