Windows could not configure one or more system components

I'm trying to upgrade an XP Tablet edition to Vista business (in place
upgrade), and the upgrade goes all the way to the completing upgrade phase
(and goes about half through that as well), then gives the error:

"Windows could not configure one or more system components. To install
Windows, restart the computer and then restart the installation".

Needless to say, I've tried it several times.

I should add that it passes the compatibility test. It says that some
devices may not work properly or will need to be updated, but that this will
not prevent the upgrade.

Ok, I've looked at the 2 other threads I could find on this topic (after
removing some words from my search; sorry, I didn't find those posts before
this one!)

Anyhow, I looked a bit through my setuperr file, and while the 2 other
threads were resolved because they noticed something to do with IIS, mine
does not. It does have to do with IaSservice, but this doesn't seem to exist
in XP.