header search bug

I realise that this theme wasn't intended to have a header search, but it works well on my sites (I use this theme, slightly modified, on 3 sites, it's great!). only problem is that the search box doesn't work! this is the fix:
. the code was thus:

   <?php if ($search_box): ?>
     <form action=" <?php print url("search") ?> " method="post">
    <div id="search">
      <input class="form-text" type="text" size="15" value="" name="edit[keys]" id="edit-keys" /> <input class="form-submit" name="op" type="submit" value="<?php print t("Search")?>" />
    </div>
  </form>
   <?php endif; ?>

simply changed it to be the same as the bluemarine theme:

   <?php if ($search_box): ?>
      <?php print $search_box ?>
   <?php endif; ?>

and it works fine!