I had a similar problem on my home network when I set the DHCP flag in
the conf/hosts file to 1. Setting it to 0 seemed to fix that problem.
Since I don't have a DNS server on my home network I'm guessing it
wasn't able to properly query the router for DHCP information, but it
was still able to
Sorry if you've already covered this issue, but I'm assuming this backup takes a very long time over a 1mbps ADSL connection. From what I remember, BackupPC has a timeout on backups defined and will stop a backup if it lasts longer then that defined time. (I believe you can modify this time