title: pdo execute gives 500 internal server error
body: <pre><code>$dbh= new PDO('mysql:host=127.0.0.1;dbname=prawntube', "uname", "aaaaa");
  $s=$dbh-&gt;prepare("call smessage_select(:sm,:lang)");
  $s-&gt;bindParam(":sm", $sm,PDO::PARAM_STR);
  $s-&gt;bindParam(":lang", $lang,PDO::PARAM_STR);
  /*
      $dbh-&gt;execute();
      $title=$s-&gt;fetch();
  */
  </code></pre>
  
  <p>when I comment out the segment, I have no errors. Otherwise, I get internal server error 500. I am using mysql driver and my connection string is fine. Any guesses?</p>