diff --git a/libraries/common.lib.php b/libraries/common.lib.php
index 26d4e3ef69..f8f8ae649c 100644
--- a/libraries/common.lib.php
+++ b/libraries/common.lib.php
@@ -450,6 +450,8 @@ function PMA_showMySQLDocu($chapter, $link, $big_icon = false, $anchor = '', $ju
                 $mysql = '5.5';
             } else if (PMA_MYSQL_INT_VERSION >= 50100) {
                 $mysql = '5.1';
+            } else {
+                $mysql = '5.0';
             }
         }
         $url = $cfg['MySQLManualBase'] . '/' . $mysql . '/' . $lang . '/' . $link . '.html';