Index: t3lib/cache/backend/class.t3lib_cache_backend_filebackend.php
===================================================================
--- t3lib/cache/backend/class.t3lib_cache_backend_filebackend.php	(revision 5563)
+++ t3lib/cache/backend/class.t3lib_cache_backend_filebackend.php	(working copy)
@@ -75,7 +75,7 @@
 	 * @author Ingo Renner <ingo@typo3.org>
 	 */
 	public function setCacheDirectory($cacheDirectory) {
-		$documentRoot = t3lib_div::getIndpEnv('TYPO3_DOCUMENT_ROOT') . '/';
+		$documentRoot = PATH_site;
 
 			// resetting if an absolute path is given
 		if ($cacheDirectory{0} == '/') {