Index: t3lib/class.t3lib_befunc.php
===================================================================
--- t3lib/class.t3lib_befunc.php	(revision 5105)
+++ t3lib/class.t3lib_befunc.php	(working copy)
@@ -4008,7 +4008,9 @@
 				$warnings['install_enabled'] = sprintf(
 					$GLOBALS['LANG']->sL('LLL:EXT:lang/locallang_core.xml:warning.install_enabled'),
 					'<span style="white-space:nowrap;">'.$enableInstallToolFile.'</span>');
-				$warnings['install_enabled'].= ' <a href="'.$url.'">'.$GLOBALS['LANG']->sL('LLL:EXT:lang/locallang_core.xml:warning.install_enabled_cmd').'</a>';
+				if (is_writable($enableInstallToolFile)) {
+					$warnings['install_enabled'].= ' <a href="'.$url.'">'.$GLOBALS['LANG']->sL('LLL:EXT:lang/locallang_core.xml:warning.install_enabled_cmd').'</a>';
+				}
 			}
 
 				// Check if the encryption key is empty