Issue #2074123 - Fixed a bug with the "Disable login failure error message" feature. A recent change in Drupal core (7.23 release), caused this feature to stop working. This and corresponding simpletests now work!
Development version of the login_security module for the drupal-6 core version. It's just a port modifying only those major changes of core version as in: Overview of Drupal API changes in 6.x (http://drupal.org/node/144132).
This module should be tested before being release as estable.. I did test in windows using mysql and works as expected.