[libvirt] Fail to import available VM image

hi, i am trying to import an available KVM image to use with libvirt. i am not sure if this is the problem of libvirt or not, so bear in me if that is not the case. i run the following command, and got error: # virt-install -n winxp -r 800 -f img.winxp --accelerate --vnc --noautoconsole -v --import ERROR [Errno 10] No child processes all the softwares are of latest version (libvirt 0.9.10 and virtinst-0.60.1) where am i wrong? many thanks, Jun