[Fedora-xen] virt-install on FC7 gives errors - why ?

Helllo, 1) I had installed FC7 on x86_64 machine; I am running the default FC7 Xen domain 0 on it. I tried to install FC7 guest (also x86_64) by virt-install. This guest should be paravirualized (I don't have support for full virtualization on this CPU). What I did was: virt-install -b --vcpus=1 -n guset4 -r 256 -s 4 -f /mnt/sda5/xenguest/guest4 -l http://192.168.0.131/ftp/ -p --nographics on http://192.168.0.131/ftp/ there is the FC7 installation tree ; This machines runs an apache http server. What I see on the screen is: ... ... Starting install... libvir: Xen Daemon error : GET operation failed: libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name libvir: error : configuration file syntax error: expecting a name Retrieving Fedora... 491 kB 00:00 Retrieving vmlinuz... 100% |=========================| 1.8 MB 00:01 Retrieving initrd.img... 100% |=========================| 5.4 MB 00:01 libvir: Xen Daemon error : GET operation failed: Creating storage file... 100% |=========================| 4.0 GB 00:00 ... them (eventually the guest ** is not ** created).? about which configuration file is this error message? 2) A second question: from running "virt-install --help" I see that I can choose -b (for bridging) optionally with a bridge name. I can also choose -w NETWORK for connecting to a nic. My question is: must I add "-b" or "-w" ? or is there some default behaviour if I don't select any of these options? Regards, Ian