I can confirm this too and it seems like changing value with gconf- editor from <apps/gnome-btdownload/settings/max_port> larger than default 6881 fixes this. Maybe it should be set default to larger value?
-- "Address already in use" error with multiple downloads https://launchpad.net/bugs/57039 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs