Make CI_FTP::mkdir()'s first parameter mandatory (optional doesn't make sense)
diff --git a/system/libraries/Ftp.php b/system/libraries/Ftp.php
index 2489f49..84ecf13 100644
--- a/system/libraries/Ftp.php
+++ b/system/libraries/Ftp.php
@@ -247,7 +247,7 @@
 	 * @param	int	$permissions
 	 * @return	bool
 	 */
-	public function mkdir($path = '', $permissions = NULL)
+	public function mkdir($path, $permissions = NULL)
 	{
 		if ($path === '' OR ! $this->_is_conn())
 		{