Index: typo3/sysext/cms/tslib/class.tslib_pibase.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_pibase.php	(revision 4691)
+++ typo3/sysext/cms/tslib/class.tslib_pibase.php	(working copy)
@@ -801,10 +801,10 @@
 	 * @return	string		HTML content wrapped, ready to return to the parent object.
 	 */
 	function pi_wrapInBaseClass($str)	{
-		$content = '<div class="'.str_replace('_','-',$this->prefixId).'">
-		'.$str.'
-	</div>
-	';
+		$content = $str ? '<div class="' . str_replace('_', '-', $this->prefixId) . '">
+		' . $str . '
+		</div>
+		' : '';
 
 		if(!$GLOBALS['TSFE']->config['config']['disablePrefixComment'])	{
 			$content = '