What has happened is that the installation of the new DXTBmp has installed a newer set of dlls to the system and these are not compatible with FSDS1/2. The update places a compatible version into the FSDS program folder so it will use that instead.
I think Louis modified the FSDS3 code so that it will run with any version of mwgfx but the previous versions required a specific mwgfx.dll
