[libvirt-users] Problem creating VM: "tap: not a valid disk type"

Hi, I am having problems creating VMs in virt-manager. I have played with different xen hypervisor versions 3.0 & 3.4 (with rpm -i --force) but have in principle gone back to the originals. - Though I cannot absolutely exclude that something has gone wrong. In principle I am using rhel 5.4 with the gitco xen 3.4 hypervisor. Can anybody put me on the right track with the attached error message? Note, the storage file I am attempting to use does exist. Many thanks, Arik === Unable to complete install 'libvirt.libvirtError POST operation failed: xend_post: error from xen daemon: (xend.err 'Error creating domain: Invalid Configuration: tap: not a valid disk type') Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/create.py", line 1485, in do_install dom = guest.start_install(False, meter = meter) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 628, in start_install return self._do_install(consolecb, meter, removeOld, wait) File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 726, in _do_install self.domain = self.conn.createLinux(install_xml, 0) File "/usr/lib64/python2.4/site-packages/libvirt.py", line 1077, in createLinux if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self) libvirtError: POST operation failed: xend_post: error from xen daemon: (xend.err 'Error creating domain: Invalid Configuration: tap: not a valid disk type') '