euca-describe-images: UnknownError: An unknown error has occurred. Please try your request again.

I was following the tutorial(http://wiki.openstack.org/InstallFromSource) to install nova in my ubuntu(lucid), but failed at this step:
euca-describe-images
UnknownError: An unknown error has occurred. Please try your request again.

running uec-publish-tarball also failed:
Unable to run euca-describe-images. Is euca2ools environment set up?

euca2ools environment has been set up by running 'source novarc'.

in the log file,
(nova.api): TRACE: File "/usr/local/lib/python2.6/dist-packages/glance-2011.3-py2.6.egg/glance/common/client.py", line 146, in do_request
(nova.api): TRACE: raise exception.NotFound

these are lines around line 146:

117 if hasattr(body, 'read') and method.lower() in ('post', 'put'):
118 # Chunk it, baby...
119 c.putrequest(method, action)
120
121 for header, value in headers.items():
122 c.putheader(header, value)
123 c.putheader('Transfer-Encoding', 'chunked')
124 c.endheaders()
125
126 chunk = body.read(self.CHUNKSIZE)
127 while chunk:
128 c.send('%x\r\n%s\r\n' % (len(chunk), chunk))
129 chunk = body.read(self.CHUNKSIZE)
130 c.send('0\r\n\r\n')
131 else:
132 # Simple request...
133 c.request(method, action, body, headers)
134 res = c.getresponse()
135 status_code = self.get_status_code(res)
136 if status_code in (httplib.OK,
137 httplib.CREATED,
138 httplib.ACCEPTED,
139 httplib.NO_CONTENT):
140 return res
141 elif status_code == httplib.UNAUTHORIZED:
142 raise exception.NotAuthorized
143 elif status_code == httplib.FORBIDDEN:
144 raise exception.NotAuthorized
145 elif status_code == httplib.NOT_FOUND:
146 raise exception.NotFound
147 elif status_code == httplib.CONFLICT:
148 raise exception.Duplicate(res.read())
149 elif status_code == httplib.BAD_REQUEST:
150 raise exception.Invalid(res.read())
151 elif status_code == httplib.INTERNAL_SERVER_ERROR:
152 raise Exception("Internal Server error: %s" % res.read())
153 else:
154 raise Exception("Unknown error occurred! %s" % res.read())

 but I do not kown whats not found.

this is the full log:

2011-07-31 14:47:07,994 DEBUG nova.auth.manager [-] Looking up user: '2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b' from (pid=19204) authenticate /home/joychan/open-2stack/nova/nova/auth/manager.py:277
2011-07-31 14:47:07,996 DEBUG nova.auth.manager [-] user: User('swsuser', 'swsuser', '2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b', 'd6671681-cb8b-4aec-a9b0-d4f51d187a9e', True) from (pid=19204) authenticate /home/joychan/open-2stack/nova/nova/auth/manager.py:279
2011-07-31 14:47:08,006 DEBUG nova.signer [-] using _calc_signature_2 from (pid=19204) _calc_signature_2 /home/joychan/open-2stack/nova/nova/auth/signer.py:126
2011-07-31 14:47:08,006 DEBUG nova.signer [-] query string: AWSAccessKeyId=2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b%3Asinasws&Action=DescribeImages&Owner.1=self&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2011-07-31T06%3A47%3A07&Version=2009-11-30 from (pid=19204) _calc_signature_2 /home/joychan/open-2stack/nova/nova/auth/signer.py:142
2011-07-31 14:47:08,007 DEBUG nova.signer [-] string_to_sign: GET
192.168.1.106:8773
/services/Cloud/
AWSAccessKeyId=2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b%3Asinasws&Action=DescribeImages&Owner.1=self&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2011-07-31T06%3A47%3A07&Version=2009-11-30 from (pid=19204) _calc_signature_2 /home/joychan/open-2stack/nova/nova/auth/signer.py:144
2011-07-31 14:47:08,007 DEBUG nova.signer [-] len(b64)=44 from (pid=19204) _calc_signature_2 /home/joychan/open-2stack/nova/nova/auth/signer.py:147
2011-07-31 14:47:08,007 DEBUG nova.signer [-] base64 encoded digest: f/J9EZgXGncf79T4q6cXmyErB6Uhala6yKBVLT6HDq4= from (pid=19204) _calc_signature_2 /home/joychan/open-2stack/nova/nova/auth/signer.py:148
2011-07-31 14:47:08,007 DEBUG nova.auth.manager [-] user.secret: d6671681-cb8b-4aec-a9b0-d4f51d187a9e from (pid=19204) authenticate /home/joychan/open-2stack/nova/nova/auth/manager.py:322
2011-07-31 14:47:08,007 DEBUG nova.auth.manager [-] expected_signature: f/J9EZgXGncf79T4q6cXmyErB6Uhala6yKBVLT6HDq4= from (pid=19204) authenticate /home/joychan/open-2stack/nova/nova/auth/manager.py:323
2011-07-31 14:47:08,007 DEBUG nova.auth.manager [-] signature: f/J9EZgXGncf79T4q6cXmyErB6Uhala6yKBVLT6HDq4= from (pid=19204) authenticate /home/joychan/open-2stack/nova/nova/auth/manager.py:324
2011-07-31 14:47:08,008 AUDIT nova.api [c759a440-75f0-4c98-8dbc-697014019ee8 swsuser sinasws] Authenticated Request For swsuser:sinasws)
2011-07-31 14:47:08,008 DEBUG nova.api [-] action: DescribeImages from (pid=19204) __call__ /home/joychan/open-2stack/nova/nova/api/ec2/__init__.py:217
2011-07-31 14:47:08,008 DEBUG nova.api [-] arg: Owner.1 val: self from (pid=19204) __call__ /home/joychan/open-2stack/nova/nova/api/ec2/__init__.py:219
2011-07-31 14:47:08,011 ERROR nova.api [c759a440-75f0-4c98-8dbc-697014019ee8 swsuser sinasws] Unexpected error raised: None
(nova.api): TRACE: Traceback (most recent call last):
(nova.api): TRACE: File "/home/joychan/open-2stack/nova/nova/api/ec2/__init__.py", line 325, in __call__
(nova.api): TRACE: result = api_request.invoke(context)
(nova.api): TRACE: File "/home/joychan/open-2stack/nova/nova/api/ec2/apirequest.py", line 78, in invoke
(nova.api): TRACE: result = method(context, **args)
(nova.api): TRACE: File "/home/joychan/open-2stack/nova/nova/api/ec2/cloud.py", line 1342, in describe_images
(nova.api): TRACE: images = self.image_service.detail(context)
(nova.api): TRACE: File "/home/joychan/open-2stack/nova/nova/image/s3.py", line 78, in detail
(nova.api): TRACE: return self.service.detail(context)
(nova.api): TRACE: File "/home/joychan/open-2stack/nova/nova/image/glance.py", line 114, in detail
(nova.api): TRACE: limit=limit)
(nova.api): TRACE: File "/usr/local/lib/python2.6/dist-packages/glance-2011.3-py2.6.egg/glance/client.py", line 86, in get_images_detailed
(nova.api): TRACE: res = self.do_request("GET", "/images/detail", params=params)
(nova.api): TRACE: File "/usr/local/lib/python2.6/dist-packages/glance-2011.3-py2.6.egg/glance/client.py", line 56, in do_request
(nova.api): TRACE: headers, params)
(nova.api): TRACE: File "/usr/local/lib/python2.6/dist-packages/glance-2011.3-py2.6.egg/glance/common/client.py", line 146, in do_request
(nova.api): TRACE: raise exception.NotFound
(nova.api): TRACE: NotFound: None
(nova.api): TRACE:
2011-07-31 14:47:08,012 ERROR nova.api [c759a440-75f0-4c98-8dbc-697014019ee8 swsuser sinasws] Environment: {"HTTP_AUTHORIZATION": "AWS 2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b:sinasws:Tu2Cev5LCmgIaBQbs87WgtWRKWA=", "CONTENT_TYPE": "text/plain", "SCRIPT_NAME": "/services/Cloud", "HTTP_DATE": "Sun, 31 Jul 2011 06:47:07 GMT", "REQUEST_METHOD": "GET", "HTTP_HOST": "192.168.1.106:8773", "PATH_INFO": "/", "SERVER_PROTOCOL": "HTTP/1.0", "QUERY_STRING": "AWSAccessKeyId=2b447c65-2ca7-4dfb-8bfb-28d691f8ed6b%3Asinasws&Action=DescribeImages&Owner.1=self&SignatureMethod=HmacSHA256&SignatureVersion=2&Timestamp=2011-07-31T06%3A47%3A07&Version=2009-11-30&Signature=f/J9EZgXGncf79T4q6cXmyErB6Uhala6yKBVLT6HDq4%3D", "CONTENT_LENGTH": "0", "HTTP_USER_AGENT": "Boto/1.9b (linux2)", "SERVER_NAME": "192.168.1.106", "REMOTE_ADDR": "192.168.1.106", "wsgi.url_scheme": "http", "SERVER_PORT": "8773", "GATEWAY_INTERFACE": "CGI/1.1", "HTTP_ACCEPT_ENCODING": "identity"}
2011-07-31 14:47:08,012 ERROR nova.api [c759a440-75f0-4c98-8dbc-697014019ee8 swsuser sinasws] UnknownError: An unknown error has occurred. Please try your request again.
2011-07-31 14:47:08,013 INFO nova.api [c759a440-75f0-4c98-8dbc-697014019ee8 swsuser sinasws] 0.19459s 192.168.1.106 GET /services/Cloud/ CloudController:DescribeImages 400 [Boto/1.9b (linux2)] text/plain text/xml