diff --git a/install/lib/installer_base.lib.php b/install/lib/installer_base.lib.php
index d5f200661fa664346d75502ddd2a192e3a57b6e4..f193c7d5345e8257439b12ef3c086dbe49e3ea50 100644
--- a/install/lib/installer_base.lib.php
+++ b/install/lib/installer_base.lib.php
@@ -777,7 +777,7 @@ class installer_base {
 			$virtual_domains = "' '";
 
 		$content = str_replace('{hostname}', $conf['hostname'], $content);
-		if(!isset($old_options['DEFAULT_SERVER_LANGUAGE']) || $old_options['DEFAULT_SERVER_LANGUAGE'] == '') $old_options['DEFAULT_SERVER_LANGUAGE'] = 'en';
+		if(!isset($old_options['DEFAULT_SERVER_LANGUAGE']) || $old_options['DEFAULT_SERVER_LANGUAGE'] == '') $old_options['DEFAULT_SERVER_LANGUAGE'] = "'en'";
 		$content = str_replace('{default_language}', $old_options['DEFAULT_SERVER_LANGUAGE'], $content);
 		$content = str_replace('{virtual_domains}', $virtual_domains, $content);