Thank for your reply,
I changed code and leightbox shows ok. But I have some detail questions:
Question 1: I have to manual assign element to theme? How to assign automatic  as column(row) theme?
Question 2: An element with required rule, how rule element'is assigned here?
Question 3: I want to validate at client, I call validate_form_name on click submit, but undefined error.
document.tpl theme
<center>
<BR>
<table>
	<tr>		
		<td>
			{$form_open}
			<table cellpadding="0" style="width:550px; border-spacing: 3px;">
				<tr>
				<td class="epesi_label" style="width:13%;">
					{$form_area.label}
				</td>
				<td class="epesi_data" style="width:53%;">
					<div style="position: relative;">
						{$form_area.error} // Question 2: How rule element'is assigned here?
						{$form_area.html}
					</div>					
				</td>				
				</tr>
				<tr>
				<td>
				</td>
				<td>					
					{$form_submit.html}
				</td>				
				</tr>
			</table>			
			{$form_close}
		</td>
	</tr>
</table>
</center>
public function new_form($prompt_id)
	{		
		$form = & $this->init_module('Libs/QuickForm');
		$theme = Base_ThemeCommon::init_smarty();
				
		$area = $form->addElement('text','area',__('Area'));
		$form->addRule('area', 'Required', 'required', null, 'client'); //An element with required rule
		
                // Question 1: I have to manual assign element to theme? How to automatic assign as column(row) theme?
		$theme->assign('form_area', array(
							'label'=>__('Area'),
							'html'=>$area->toHtml()										
							));
	
                // Question 3: I want to validate at client, I call validate_form_name on click submit, but undefined error.
		$submit = $form->addElement('submit', 'add_new', 'Add', array('onclick'=>'validate_' . $form->get_name(). '(frm)'. ';leightbox_deactivate("'.$prompt_id.'")'));
							
		$theme->assign('form_submit', array(
							'html'=>$submit->toHtml()										
							));
							
		if($form->validate())
		{	
			$values = $form->exportValues();
			print_r($values);			
		}
		
		$form->add_error_closing_buttons();
		
		$form->assign_theme('form', $theme);
		ob_start(); 
		Base_ThemeCommon::display_smarty($theme,'Custom_Document','document');
		$profiles_out = ob_get_clean();
        return $profiles_out;
	}