Office 2007 Setup .NET Runtime Error in Wizard.exe

I have Office 2007 Pro Plus up and running smoothly. But when I try to
install Business Contact Manager, the setup fails almost immediately. If I
try to re-run the Office 2007 setup, I get the same error, even though Office
2007 setup was previously working. I have installed a number of changes and
upgrades in the interim, including installing .NET 3.5 SP1 (which also
includes updates to earlier versions of .NET). Suspecting the .NET 3.5
upgrade might be the culprit, I uninstalled and then re-installed it, to no
avail. Setups that only use setup.exe and/or an msi do not cause a problem.
Only setups that use wizard.exe

Here's what happens:

Dialog shows: Microsoft Office Small Business Setup Wizard has encountered
a problem and needs to close. We are sorry for the inconvenience.

Event Log shows .NET Runtime 2.0 Error:
EventType clr20r3, P1 wizard.exe, P2 2.0.7024.0, P3 453e0a98, P4
system.configuration, P5, P6 4889de74, P7 1a6, P8 136, P9
ioibmurhynrxkw0zxkyrvfn0boyyufow, P10 NIL.

Debugger shows unhandled kernel exception in wizard.exe.

Would appreciate help fixing this problem.