diff --git a/htdocs/master.inc.php b/htdocs/master.inc.php
index 2967e94cdca444b25a23e7af2e8a3a2a99d56a55..e722cf994125074d51ef3a4771dc219195c4eec7 100644
--- a/htdocs/master.inc.php
+++ b/htdocs/master.inc.php
@@ -77,8 +77,8 @@ if (empty($dolibarr_main_db_host))
 }
 if (empty($dolibarr_main_url_root))
 {
-	print 'Value for parameter dolibarr_main_url_root is not defined in your conf.php file'."\n";
-	print 'You must add here your Dolibarr full Url (Example: http://mydomain/myurl/)'."\n";
+	print 'Value for parameter \'dolibarr_main_url_root\' is not defined in your \'htdocs\conf\conf.php\' file.<br>'."\n";
+	print 'You must add this parameter with your full Dolibarr root Url (Example: http://myvirtualdomain/ or http://mydomain/mydolibarrurl/)'."\n";
 	exit;
 }
 if (empty($dolibarr_main_db_type)) $dolibarr_main_db_type='mysql';   // Pour compatibilite avec anciennes configs, si non defini, on prend 'mysql'