I am unable to provision a new libvirt guest on Xen.

Foreman version is 1.1
Foreman host OS is ubuntu 12.0.4
Foreman install method is from ubuntu repository.
Libvirt on compute resource is 0.9.6
Compute resource URL: xen+ssh://root@xen8
I added foreman ssh key for root on xen8.

Started POST "/hosts" for 192.168.2.180 at Wed Apr 10 15:29:18 +0100 2013
   Processing by HostsController#create as
   Parameters: {"utf8"=>"✓", "capabilities"=>"build", "host"=>{"progress_report_id"=>"[FILTERED]", "build"=>"1", "model_id"=>"", "puppetclass_ids"=>[""], "root_pass"=>"[FI      LTERED]", "ip"=>"192.168.5.211", "updated_at"=>"1365604118", "medium_id"=>"3", "ptable_id"=>"2", "name"=>"frodo", "compute_resource_id"=>"4", "puppet_proxy_id"=>"1", "do      main_id"=>"1", "disk"=>"", "subnet_id"=>"1", "architecture_id"=>"1", "enabled"=>"1", "environment_id"=>"2", "managed"=>"true", "comment"=>"", "overwrite"=>"false", "inter      faces_attributes"=>{"new_interfaces"=>{"type"=>"Nic::Managed", "_destroy"=>"false", "ip"=>"", "name"=>"", "domain_id"=>"1", "provider"=>"IPMI", "mac"=>""}}, "operatingsys      tem_id"=>"3", "hostgroup_id"=>"1", "compute_attributes"=>{"cpus"=>"1", "memory"=>"805306368", "nics_attributes"=>{"new_nics"=>{"bridge"=>"br7", "_delete"=>""}, "0"=>{"bri      dge"=>"br0", "_delete"=>""}}, "volumes_attributes"=>{"new_volumes"=>{"pool_name"=>"default", "format_type"=>"raw", "capacity"=>"10G", "_delete"=>""}, "0"=>{"pool_name"=>"      default", "format_type"=>"raw", "capacity"=>"10G", "_delete"=>""}}, "start"=>"1"}, "mac"=>"", "provision_method"=>"build"}, "authenticity_token"=>"axsjjfuxRmVCsThcgSlgyj4      HpVt4FhEuAV5t9/DMTYM="}
Adding Compute instance for frodo.example.com
Rolling back due to a problem: Settings up compute instance frodo.example.com   1       failed  frodo.example.comsetCompute
Failed to save:
Rendered hosts/_progress.erb (0.1ms)
Rendered puppetclasses/_selectedClasses.html.erb (0.0ms)
Rendered puppetclasses/_classes.html.erb (196.2ms)
Rendered puppetclasses/_class_selection.html.erb (203.3ms)
Rendered compute_resources_vms/form/libvirt/_network.html.erb (2024.4ms)
Rendered compute_resources_vms/form/libvirt/_network.html.erb (1909.1ms)
Rendered compute_resources_vms/form/libvirt/_volume.html.erb (27.6ms)
Rendered compute_resources_vms/form/libvirt/_volume.html.erb (23.9ms)
Rendered compute_resources_vms/form/_libvirt.html.erb (4245.6ms)
Rendered hosts/_compute.html.erb (4261.7ms)
Rendered common/_domain.html.erb (7.2ms)
Rendered hosts/_interfaces.html.erb (8.1ms)
Rendered common/os_selection/_architecture.html.erb (153.3ms)
Rendered common/os_selection/_operatingsystem.html.erb (5.5ms)
Rendered hosts/_operating_system.erb (163.9ms)
Rendered hosts/_unattended.html.erb (4448.1ms)
Rendered puppetclasses/_class_parameters.html.erb (0.0ms)
Rendered puppetclasses/_classes_parameters.html.erb (5.7ms)
Rendered common_parameters/_inherited_parameters.erb (0.8ms)
Rendered common_parameters/_puppetclass_parameter.erb (1.9ms)
Rendered common_parameters/_puppetclasses_parameters.erb (3.1ms)
Rendered common_parameters/_parameter.erb (1.2ms)
Rendered common_parameters/_parameters.erb (2.4ms)
Rendered hosts/_form.html.erb (4685.6ms)
Read fragment views/tabs_and_title_records-1 (0.2ms)
Rendered home/_topbar.rhtml (1.5ms)
Rendered hosts/new.html.erb within layouts/application (4691.3ms)
Completed 200 OK in 4839ms (Views: 4689.8ms | ActiveRecord: 4.4ms)