virt-install fails because missing 'guest' node in the xml

Binary package hint: python-virtinst

1)
Ubuntu version : 9.04

2)
Package release : 0.400.1-2ubuntu2

3)
when trying to install a new virtual machine using virt-install using all the good options, I hope it works properly

4)
when trying to install a new virtual machine I have the following error :
virt-install -n foo -r 512 -f foo.vm -s 400 -c iso/jeos.iso --accelerate --connect=qemu:///system --vnc --noautoconsole -v
ERROR Unsupported virtualization type 'hvm'

It seems there is no guest node (never append any Guest in Capabilities.parseXML) so the Capabilities.guestForOSType return a None object !
After adding some print commands in the source code I see that conn.getCapabilities return the following xml :
<capabilities>
  <host>
    <cpu>
      <arch>x86_64</arch>
    </cpu>
  </host>
</capabilities>

So the Capabilities object only have the host property and no guests...

FINALLY :
- is the error message is correct (if guest is a None object it's not because of the virtualization type) ?
- is it possible to raise an error if no guest is found ?
- anything else ????

I had been able to reproduce this error on multiple servers for both ubuntu and fedora.