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 BG Road Maps, which might be related to flexMIRT.