I apologise if this has already been answered. tut.tgz is a tarred and gziped archive. It looks like you have managed to decompress the archive (so it is no longer gzipped). You now need to untar it. To do this you need tar for windows, which can be found at http://gnuwin32.sourceforge.net/packages/tar.htm. Other programs may also untar.
Winzip (which is widespread) does both at once, but it's important to have .tgz not .tar.gz as extension.
all the best, Thomas