Many people have been disappointed on the deprication of Windows Movie Maker v6.x on Windows 7. Microsoft seems to have taken a back step with Windows Live Movie Maker.
However the good news is that the Vista version of Windows Movie Maker v6.x would work fine on Windows 7 if ported correctly froma vista machine. Please use the instrcutions put together by Blaine here:
http://movies.blainesville.com/2010/05/installing-windows-movie-maker-60-on.html
If you have installed WMM from any other site I would suggest uninstall and re-install from the above link. This is especially important if you are using 64 bit flavour of Windows 7.
Afterwards reinstall ShaderTFX.
