"There was a problem connecting to the server" in iTunes after migrating to new mac

I have a problem that is driving me crazy with my brand new iMac. I see many other people posting similar issues, but none of the other solutions seem to work for me.

I had a MacPro and bought a new iMac, on which I used Migration Assistant to set up. So the new iMac is virtually the same as my old machine in terms of appearance and installed applications. Both machines have Mountain Lion 10.8.2. All software on both machines has been through Software Update and is fully up to date, as are the connected devices (iPhone and iPad).

The problem is with iTunes. Every time I start iTunes (I think at the moment it checks my two connected devices) I get a pop up dialogue saying:

There was a problem connecting to the server "MacPro".

The server may not exist or it is unavailable at this time. Check the server name or IP address, check your network connection, and then try again.

This dialogue continues to pop up constantly as long as iTunes is open, interrupting my work and frustrating me no end. The old machine is of course turned off and indeed is not available -- but I can't find what on the new iMac is so desperate to connect to it.

So far I have tried completing erasing my iTunes library, deleting all the preferences, reinstalling iTunes from a fresh download of the dmg, safe rebooting several times with no peripherals connected at all, and deleteing other preferences like the Login Items, iPhone config and iPhoto. I have also cleared Recent Items from the apple menu and opened "Connect to Server" in the finder and cleared all servers from the dropdown menu.

Last night I also completely restored my iPhone from scratch to see if that would clear away the issue and I have connected both iPhone and iPad to go through any apps that have permission to write content to my computer and deleted all of them completely from the devices.

Nothing has changed at all after all that, and I have run out of ideas. Clearly there is something somewhere that has my old machine's name hard coded in it but I can't see any way to search for it. I would grep my Library folder but I think a lot of the files are binary so I'm not sure that would unearth anything. I've seen many posts saying that Apple phone support (which I would qualify for) can't help with this issue and so I have put off phoning them to simply run through all the things I've already tried.

Any advice that anyone could offer would be extremely helpful. I can't use iTunes at all like this as it disrupts everything I try to do on the new machine.

many thanks!!