No joy installing Whidbey Preview…

After downloading the gigantic Whidbey Preview (available at MSDN Subscriber Downloads) and attempting to install it on my sacrificial machine, I reliably get a problem while installing .NET Framework 2.0: “RegSvcs.exe triggers “Memory at 0x00143cb0 tried to write to 0x00143cb0. The memory could not be ‘written.'” This happens whether I use the main installer or try to install the framework from its subdirectory. YMMV, of course.