Have you downloaded the .net framework yet? Just use Craxtion v3.1, as that is the best one out of the series.
Well, the only way to get Xbox games onto your Computer is by downloading them or sending them from your Xbox to PC. Here is an FTP guide: http://webpages.charter.net/modchipzone/ftpingproblem.htm Also, you can use Craxtion 4 to rip the disc in your Xbox to your computer. That is the best thing to do if you do not have an upgraded HD.