Just thought I’d drop the hint: I was installing VS.NET 2005 Beta 1 on a new PC today, and hit an error during the Device Emulator install, which occurs after VS.NET is installed (thankfully).  If you get an error essentially saying ‘…Error 1603…Fatal Error during installation…”, the following blog entry will help immensely:

http://blogs.msdn.com/amit_chopra/archive/2004/07/07/175484.aspx

Their proposed ‘solution’ worked perfectly.