You could have downloaded flexMIRT 3.51 from our software library for free. FlexMIRT relates to Education Tools. This software was originally created by Vector Psychometric Group.
From the developer:
flexMIRT is a multilevel, multidimensional, and multiple group item response theory (IRT) software package for item analysis and test scoring. flexMIRT® fits a variety of unidimensional and multidimensional item response theory models (also known as item factor analysis models) to single-level and multilevel data in any number of groups. It has an intuitive syntax and can be run seamlessly in a command line mode for high volume production.
You may want to check out more software, such as Avantage BPM Foundation, Adding Machine or PC-Display, which might be related to flexMIRT.