That's a bug in jaunty's libvirt. This is the upstream patch that fixes it:
http://libvirt.org/git/?p=libvirt.git;a=commit;h=9fa79000ecc883c699a6cb1ce7f00c34881bc8fe ** Package changed: virt-manager (Ubuntu) => libvirt (Ubuntu) -- Unable to create virtual machine: unknown parameter 'fmt' https://bugs.launchpad.net/bugs/518854 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to libvirt in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs