In one of the earlier versions there were some trouble reported about running on Vista. This was related to the GflAx.dll file that could not be registered correctly. Here is a work around for this. Open the register.bat file with a text editor and add the full path in front of the GflAx.dll filename (so the path where you installed the tool). Then use the "Run as administrator" option to register the DLL. After that ModelConverterX should work fine.