diff --git a/lib/engine.rb b/lib/engine.rb
--- a/lib/engine.rb
+++ b/lib/engine.rb
@@ -117,7 +117,7 @@
       Dir.chdir grading_dir
       cmd = "#{problem_home}/script/judge #{language} #{fname}"
       talk "CMD: #{cmd}"
-      system(cmd)
+      system("ruby " + cmd)
     end
 
     def get_std_script_dir
diff --git a/std-script/compile b/std-script/compile
--- a/std-script/compile
+++ b/std-script/compile
@@ -23,9 +23,9 @@
   end
 end
 
-C_COMPILER = "/usr/bin/gcc"
-CPLUSPLUS_COMPILER = "/usr/bin/g++"
-PASCAL_COMPILER = "/usr/bin/fpc"
+C_COMPILER = "gcc"
+CPLUSPLUS_COMPILER = "g++"
+PASCAL_COMPILER = "fpc"
 
 C_OPTIONS = "-O2 -s -static -std=c99 -DCONTEST -lm -Wall"
 CPLUSPLUS_OPTIONS = "-O2 -s -static -DCONTEST -lm -Wall"
diff --git a/std-script/judge b/std-script/judge
--- a/std-script/judge
+++ b/std-script/judge
@@ -98,9 +98,11 @@
   log "ERROR: Cannot change directory to #{sandbox_dir}."
   exit(127)
 end
-execute("#{problem_home}/script/compile #{language} #{source_file}", "Compilation error!")
-compile_message = open("compiler_message").read
-compile_message.strip!
+execute("ruby #{problem_home}/script/compile #{language} #{source_file}", "Compilation error!")
+open("compiler_message") do |f|
+  compile_message = f.read
+  compile_message.strip!
+end
 call_and_log("Cannot move the compiler message to #{test_result_dir}.") {
   FileUtils.mv("compiler_message", test_result_dir)
 }
@@ -134,7 +136,7 @@
     FileUtils.cp("#{test_result_dir}/a.out", sandbox_dir)
   }
   begin
-    execute("#{problem_home}/script/run #{language} #{test_num}", "Error occured during execution of the run script")
+    execute("ruby #{problem_home}/script/run #{language} #{test_num}", "Error occured during execution of the run script")
   rescue
     # do nothing
   end
@@ -166,7 +168,7 @@
   log "ERROR: Cannot change directory to #{test_result_dir}."
   exit(127)
 end
-execute("#{problem_home}/script/grade", "An error occured during grading!")
+execute("ruby #{problem_home}/script/grade", "An error occured during grading!")
 
 log
 log "All done!"
diff --git a/std-script/run b/std-script/run
--- a/std-script/run
+++ b/std-script/run
@@ -73,7 +73,7 @@
 #`cp #{problem_home}/test_cases/#{test_num}/#{input_file_name} .`
 
 # check if box is there, if not, compile it!
-if !File.exists?("#{problem_home}/script/box")
+if !File.exists?("#{problem_home}/script/box") and !File.exists?("#{problem_home}/script/box.exe")
   log "WARNING: Compiling box: to increase efficiency, it should be compile manually"
   compile_box("#{problem_home}/script/box.cc",
               "#{problem_home}/script/box")
@@ -145,7 +145,7 @@
 check_command = "#{problem_home}/script/check #{language} #{test_num}"
 log "Checking the output..."
 log check_command
-if not system(check_command)
+if not system("ruby " + check_command)
   log "Problem with check script"
   report.call("Incorrect",0,"Check script error.\n")
   exit(127)