diff --git a/program/include/iniset.php b/program/include/iniset.php
index b2cad4292..11a29034c 100644
--- a/program/include/iniset.php
+++ b/program/include/iniset.php
@@ -55,8 +55,8 @@ if (set_include_path($include_path) === false) {
 @set_time_limit(120);
 
 // include composer autoloader (if available)
-if (@file_exists('vendor/autoload.php')) {
-    require 'vendor/autoload.php';
+if (@file_exists(INSTALL_PATH . 'vendor/autoload.php')) {
+    require INSTALL_PATH . 'vendor/autoload.php';
 }
 
 // include Roundcube Framework