Hey - if you're trying to install the 120 day eval of the RTM of SCCM 2007, and you happen to be one of those RARE folks that has a public IP address on your corporate network and therefore - no proxy server installed - you're going to get an error in downloading the pre-req's for installing SCCM 2007. There is a simple workaround - go into your browser and turn on "auto-detect proxy".
Brian has a LOT more on this - take a look!
http://blogcastrepository.com/blogs/brian_tucker/archive/2007/08/29/download-bug-in-sccm-2007-rtm-120-day-eval.aspx
Doug Miller pointed out an issue that he had installing SCCM this weekend and more people are running into the problem as time goes on. There seems to be an issue with the RTM build of SCCM 2007 that sometimes, depending on your proxy settings in IE,