Update order.php

Added missing error_filetype text.

upload/admin/language/english/sale/order.php

@@ -128,3 +128,4 @@
 $_['error_warning']              = 'Warning: Please check the form carefully for errors!';
 $_['error_permission']           = 'Warning: You do not have permission to modify orders!';
 $_['error_action']               = 'Warning: Could not complete this action!';
+$_['error_filetype']			 = 'Invalid file type!';