VMware: errors booting from volume via Horizon

When using VMwareVC nova driver and VMwareVcVMDK cinder driver, booting from volume via the Horizon UI fails. The instance boots with ERROR status and the log shows "Image could not be found". In addition, the user is unable to access the instances index page in Horizon due to an error 500 (other pages work, however). Steps to reproduce:

(Using horizon)
1. Create a volume from an image
2. Boot an instance from the volume

Expected result:
1. An instance is booted from the volume successfully
2. User is redirected to the instances index page in Horizon

Actual result:
1. Instance fails to boot with status ERROR
2. User is redirected to instances index page but page fails with 500 error. In debug mode, user sees TypeError at /project/instances: string indices must be integers (see link to trace below)

Nova log error:

 Traceback (most recent call last):
   File "/opt/stack/nova/nova/compute/manager.py", line 1037, in _build_instance
     set_access_ip=set_access_ip)
   File "/opt/stack/nova/nova/compute/manager.py", line 1410, in _spawn
     LOG.exception(_('Instance failed to spawn'), instance=instance)
   File "/opt/stack/nova/nova/compute/manager.py", line 1407, in _spawn
     block_device_info)
   File "/opt/stack/nova/nova/virt/vmwareapi/driver.py", line 623, in spawn
     admin_password, network_info, block_device_info)
   File "/opt/stack/nova/nova/virt/vmwareapi/vmops.py", line 208, in spawn
     disk_type, vif_model, image_linked_clone) = _get_image_properties()
   File "/opt/stack/nova/nova/virt/vmwareapi/vmops.py", line 187, in
     instance)
   File "/opt/stack/nova/nova/virt/vmwareapi/vmware_images.py", line 184, in
     meta_data = image_service.show(context, image_id)
   File "/opt/stack/nova/nova/image/glance.py", line 290, in show
     _reraise_translated_image_exception(image_id)
   File "/opt/stack/nova/nova/image/glance.py", line 288, in show
     image = self._client.call(context, 1, 'get', image_id)
   File "/opt/stack/nova/nova/image/glance.py", line 212, in call
     return getattr(client.images, method)(*args, **kwargs)
   File "/opt/stack/python-glanceclient/glanceclient/v1/images.py", line 114, in
     % urllib.quote(str(image_id)))
   File "/opt/stack/python-glanceclient/glanceclient/common/http.py", line 272,
     return self._http_request(url, method, **kwargs)
   File "/opt/stack/python-glanceclient/glanceclient/common/http.py", line 233,
     raise exc.from_response(resp, body_str)
 ImageNotFound: Image could not be found.

Horizon error:

    Request Method: GET
    Request URL: http://10.20.72.218/project/instances/
    Django Version: 1.5.4
    Exception Type: TypeError
    Exception Value:
    string indices must be integers
    Exception Location: /opt/stack/horizon/openstack_dashboard/wsgi/../../openstack_dashboard/ dashboards/project/instances/views.py in get_data, line 92
    Python Executable: /usr/bin/python
    Python Version: 2.7.3