Strippando tutto il contenuto javascript e css, ovver lasciando solo questo:

codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">
<html>
   <head>    
       <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Gestione asili nidi</title>      
   </head>
   <body id="win">
      <div  id="header"  >
         [img]img/nidi.png[/img]         
      </div>
      <div id="container">
        <div id="menu_v">
          <h3 class="titMenu">Pratiche</h3>
          <ul class="menu2">
                  <li title="Nuova pratica" onmouseover="this.className='hover';" onmouseout="this.className='';">Nuova pratica
                  <li title="Archivio pratiche" onmouseover="this.className='hover';" onmouseout="this.className='';">Archivio pratiche[/list]
          
          <h3 class="titMenu">Graduatoria</h3>
          <ul class="menu2">
            <li title="Graduatoria aperta" onmouseover="this.className='hover';" onmouseout="this.className='';">Graduatoria aperta
            <li title="Archivio graduatoria" onmouseover="this.className='hover';" onmouseout="this.className='';">Archivio graduatorie[/list]	
          
          <h3 class="titMenu">Gestione</h3>
            <ul class="menu2">
              <li title="Gestione nidi" onmouseover="this.className='hover';" onmouseout="this.className='';">Gestione nidi
              <li title="Tabella ISEE" onmouseover="this.className='hover';" onmouseout="this.className='';">Tabella ISEE
              <li title="Fattori sociali" onmouseover="this.className='hover';" onmouseout="this.className='';">Fattori sociali[/list]
          </div>
          
          <div  id="body_">
            <h2>Nuova pratica</h2>
            <hr />
            <div dojoType="TabContainer" style="width: 100%; height: 90%;" id="test2" doLayout="true">
            <div dojoType="struts:BindDiv" id="left" label="Inserimento manuale" showError="true">
                <form action="newPratica.action" name="newPratica" method="post">
                   <h4>Modulo d'iscrizione asilo nido ddd</h4><hr />

                   <fieldset>
                     <legend>Richiedente:</legend>
                     <table width="100%" height="100%" border="1">
                       <tr>
                         <td class="tdLabel">gdsgdfgdf <label for="newPratica_da" class="label">Da: </label></td>
                         <td><input type="text" name="da" value="" id="newPratica_da"/></td>
                         <td></td>
                         <td></td>
                         <td></td>
                         <td></td>
                         <td></td>
                         <td></td>
                       </tr>
                     </table>
                   </fieldset>
                </form>
            </div>

            <div dojoType="struts:BindDiv" id="middle" style="margin-top: 20px;" label="uoload file" showError="true">
              <form id="uploadXml" onsubmit="return true;" action="uploadXml" target="" method="post">
                <table class="wwFormTable">
                  <tr>
                    <td class="tdLabel"><label for="uploadXml_fileXml" class="label">Carica file:</label></td>
                    <td><input type="file" name="fileXml" value="" id="uploadXml_fileXml"/></td>
                  </tr>
                  <tr>
                    <td colspan="2"><hr /></td>
                  </tr>
                  <tr>
                    <td colspan="2">
                      <div align="left">
                        <input type="submit" id="uploadXml_inviaFile" name="inviaFile" value="Invia"/>
                      </div>
                    </td>
                  </tr>
                </table>
              </form>
            </div>
          </div>
        </div>
      </div>
    </body>
</html>
il fieldset si vede... quindi possibilmente l'errore risiede in qualcuno di quei file javascript/css... prova ad aprire la console degli errori di Firefox e vedere se trovi qualche errore/warning lì.