DA MapEditor is an older tool that was originally written in .NET 3.5 and used Capricorn as the DA library. The original team of developers to the best of my knowledge are no longer supporting or keeping this software up-to-date.
Sichi has rewritten the dalib library, which is a library for DarkAges files, and formats. DA MapEditor is in the process of being upgraded to run off of the new library.