windows xp not seeing mac mini during migration

Hi all,

I just set up a new mac mini for my in-laws, fast-forwarding them through 15 years of technology. However, the migration from Win XP is not as seamless as Apple promises. After all the installation, the mini saw the PC, but the Migration Assistant on the PC does not see the mini. What is there to do?

Some details:

--- I verified on my router that both computers are on my LAN.

--- If it matters, the Win XP and thus the Migration Assistant is in Hungarian, as is the Lion installation. Everything is up-to-date.

--- I tried a reboot on both machines.

--- I shut down on all firewalls for the migration.

--- There is no apparent security lockdown on my router that would cause the trouble. Apart from uPNP being turned off. Is that a problem? The mac saw the PC twice...

--- Actually, after the reboot, the mini did not see the PC anymore, and before the reboot, it could see two instances of the PC, but picking either did not help as the PC was still only "looking for the mac", with an endless progress bar.

I am happy to try any networking or Windows setup, I'm just out of ideas.

Thanks!

Laszlo