Call Xerox and request the firmware for Login Failures, This was fixed a long time ago and there is no reason to make changes Client side. This link is the firmware http://www.support.xerox.com/support/workcentre-7800-series/file-download/enus.html?operatingSystem=win7&fileLanguage=en&&associatedProduct=WorkCentre-78xx-built-in%20controller&contentId=123550&from=downloads&viewArchived=false
It is a big change though from the launch firmware that ends with .04401, it is recomended to do what the techs refer to as "Altboot, forced upgrade no data backup no clone", this is a complete reload that wipes all data, and due to the massive changes it is prefered to do it that way instead of as an upgrade. Think of it like going WinXP to Windows 8, you can upgrade, but it isn't suggested.