setup.exe 2.573.2.3 crashes every time

[Andrew Schulman]

I run setup.exe, choose any mirror, accept the "Partial" list of apps to
upgrade, click Next.  The packages are downloaded, and then setup.exe crashes
with 'The instruction at "0x004f42cb" referenced memory at "0x0106ff50".  The
memory could not be "read".'  This happens every time.

Any help would be much appreciated-- I'm dead in the water right now, with some
packages uninstalled.

Thanks,
Andrew.