MOA 2009 Pro on Windows XP Home with multi-users

Can Accounting 2009 Professional be set up for multi-users, on 2 computers,
if the computers are running Windows XP Home Edition or do the computers need
to be running XP Professional? The XP Professional disc has disappeared, even
though we have the product key still.

I followed all the directions for setting up multi-users on both computers
and I'm getting the same error on both computers according to the event log -
login failed for user computername/guest. 18456

Also, on one of the computers, MOA 2009 already has a user name of Owner,
which is correct, but it has the wrong computer name. I can't remove it or
change it. How can I fix this? The error is on the computer that acts as the
server and this needs to be corrected.

Thank you,
Deb