--- typo3_src-4.3.3/typo3/sysext/cms/tslib/class.tslib_pibase_orginal.php	2010-04-27 16:55:04.000000000 +0200
+++ typo3_src-4.3.3/typo3/sysext/cms/tslib/class.tslib_pibase.php	2010-04-27 16:55:57.000000000 +0200
@@ -220,7 +220,7 @@
 		}
 		if ($GLOBALS['TSFE']->config['config']['language'])	{
 			$this->LLkey = $GLOBALS['TSFE']->config['config']['language'];
-			if ($GLOBALS['TSFE']->config['config']['language_alt'])	{
+			if (isset($GLOBALS['TSFE']->config['config']['language_alt']))	{
 				$this->altLLkey = $GLOBALS['TSFE']->config['config']['language_alt'];
 			}
 		}