nova flavor-list gives "503 Service Unavailable" while nova-manage flavor list works

me@controlnode:~$ nova-manage flavor list
m1.medium: Memory: 4096MB, VCPUS: 2, Root: 40GB, Ephemeral: 0Gb, FlavorID: 3, Swap: 0MB, RXTX Factor: 0.0
m1.large: Memory: 8192MB, VCPUS: 4, Root: 80GB, Ephemeral: 0Gb, FlavorID: 4, Swap: 0MB, RXTX Factor: 0.0
m1.tiny: Memory: 512MB, VCPUS: 1, Root: 0GB, Ephemeral: 0Gb, FlavorID: 1, Swap: 0MB, RXTX Factor: 0.0
m1.xlarge: Memory: 16384MB, VCPUS: 8, Root: 160GB, Ephemeral: 0Gb, FlavorID: 5, Swap: 0MB, RXTX Factor: 0.0
m1.small: Memory: 2048MB, VCPUS: 1, Root: 20GB, Ephemeral: 0Gb, FlavorID: 2, Swap: 0MB, RXTX Factor: 0.0

nova --debug flavor-list
connect: (152.66.xxx.xxx, 5000)
send: 'POST /v2.0/tokens HTTP/1.1\r\nHost: 152.66.xxx.xxx:5000\r\nContent-Length: 112\r\ncontent-type: application/json\r\naccept-encoding: gzip, deflate\r\naccept: application/json\r\nuser-agent: python-novaclient\r\n\r\n{"auth": {"tenantName": "openstackDemo", "passwordCredentials": {"username": "admin", "password": "adminpass"}}}'
reply: 'HTTP/1.1 200 OK\r\n'
header: Content-Type: application/json
header: Vary: X-Auth-Token
header: Date: Tue, 10 Jul 2012 11:37:11 GMT
header: Transfer-Encoding: chunked
connect: (152.66.xxx.xxy, 8774)
send: u'GET /v2/8a8ac4aae4474fbb8aafbc308dba6b1c/flavors/detail HTTP/1.1\r\nHost: xxx.xxy:8774\r\nx-auth-project-id: openstackDemo\r\nx-auth-token: 71342ca725cb4685b4ba5a3f39dfbc27\r\naccept-encoding: gzip, deflate\r\naccept: application/json\r\nuser-agent: python-novaclient\r\n\r\n'
reply: 'HTTP/1.1 503 Service Unavailable\r\n'
header: Content-Length: 100
header: Content-Type: text/plain; charset=UTF-8
header: Date: Tue, 10 Jul 2012 11:37:11 GMT
DEBUG (shell:416) string indices must be integers, not str
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/novaclient/shell.py", line 413, in main
    OpenStackComputeShell().main(sys.argv[1:])
  File "/usr/lib/python2.7/dist-packages/novaclient/shell.py", line 364, in main
    args.func(self.cs, args)
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/shell.py", line 302, in do_flavor_list
    flavors = cs.flavors.list()
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/flavors.py", line 39, in list
    return self._list("/flavors/detail", "flavors")
  File "/usr/lib/python2.7/dist-packages/novaclient/base.py", line 76, in _list
    data = body[response_key]
TypeError: string indices must be integers, not str
ERROR: string indices must be integers, not str

Environment variables:
OS_AUTH_URL="http://152.66.xxx.xxx:5000/v2.0/"
OS_PASSWORD="adminpass"
OS_REGION_NAME="myregion"
OS_TENANT_NAME="openstackDemo"
OS_USERNAME="admin"

I'm using Ubuntu server 12.04, with recently upgraded packages, this test deployment is similar to the one described in the "openstack-install-guide-essex.pdf"

This problem exists both on my compute and control node.