Rescue OSAPI command fails

I use nova revision 1204 and when I execute the OSAPI command 'rescue' (nova rescue <server ID>), I get this error in the 'nova-api' logs :

2011-06-23 17:05:37,904 DEBUG nova.api.openstack [-] Successfully authenticated 'demo' from (pid=11721) authenticate /usr/lib/pymodules/python2.6/nova/api/openstack/auth.py:111
2011-06-23 17:05:37,912 DEBUG routes.middleware [-] Matched GET /servers/83 from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:100
2011-06-23 17:05:37,912 DEBUG routes.middleware [-] Route path: '/servers/:(id)', defaults: {'action': u'show', 'controller': <nova.api.openstack.wsgi.Resource object at 0x24bded0>} from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:102
2011-06-23 17:05:37,912 DEBUG routes.middleware [-] Match dict: {'action': u'show', 'controller': <nova.api.openstack.wsgi.Resource object at 0x24bded0>, 'id': u'83'} from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:103
2011-06-23 17:05:37,913 DEBUG nova.api.openstack.wsgi [-] GET http://10.193.175.74:8774/v1.0/servers/83?fresh=1308841537.91 from (pid=11721) __call__ /usr/lib/pymodules/python2.6/nova/api/openstack/wsgi.py:360
2011-06-23 17:05:37,976 DEBUG nova.api.openstack.wsgi [-] http://10.193.175.74:8774/v1.0/servers/83?fresh=1308841537.91 returned with HTTP 200 from (pid=11721) __call__ /usr/lib/pymodules/python2.6/nova/api/openstack/wsgi.py:387
2011-06-23 17:05:37,984 DEBUG routes.middleware [-] Matched POST /servers/83/rescue from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:100
2011-06-23 17:05:37,984 DEBUG routes.middleware [-] Route path: '/servers/:(id)/rescue', defaults: {'action': u'rescue', 'controller': <nova.api.openstack.wsgi.Resource object at 0x24bded0>} from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:102
2011-06-23 17:05:37,985 DEBUG routes.middleware [-] Match dict: {'action': u'rescue', 'controller': <nova.api.openstack.wsgi.Resource object at 0x24bded0>, 'id': u'83'} from (pid=11721) __call__ /usr/lib/pymodules/python2.6/routes/middleware.py:103
2011-06-23 17:05:37,985 DEBUG nova.api.openstack.wsgi [-] POST http://10.193.175.74:8774/v1.0/servers/83/rescue from (pid=11721) __call__ /usr/lib/pymodules/python2.6/nova/api/openstack/wsgi.py:360
2011-06-23 17:05:37,986 ERROR nova.api.openstack [-] Caught error: rescue() got an unexpected keyword argument 'body'
(nova.api.openstack): TRACE: Traceback (most recent call last):
(nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.6/nova/api/openstack/__init__.py", line 60, in __call__
(nova.api.openstack): TRACE: return req.get_response(self.application)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/request.py", line 919, in get_response
(nova.api.openstack): TRACE: application, catch_exc_info=False)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/request.py", line 887, in call_application
(nova.api.openstack): TRACE: app_iter = application(self.environ, start_response)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 159, in __call__
(nova.api.openstack): TRACE: return resp(environ, start_response)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 159, in __call__
(nova.api.openstack): TRACE: return resp(environ, start_response)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 159, in __call__
(nova.api.openstack): TRACE: return resp(environ, start_response)
(nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.6/routes/middleware.py", line 131, in __call__
(nova.api.openstack): TRACE: response = self.app(environ, start_response)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 159, in __call__
(nova.api.openstack): TRACE: return resp(environ, start_response)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 147, in __call__
(nova.api.openstack): TRACE: resp = self.call_func(req, *args, **self.kwargs)
(nova.api.openstack): TRACE: File "/usr/local/lib/python2.6/dist-packages/WebOb-0.9.8-py2.6.egg/webob/dec.py", line 208, in call_func
(nova.api.openstack): TRACE: return self.func(req, *args, **kwargs)
(nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.6/nova/api/openstack/wsgi.py", line 372, in __call__
(nova.api.openstack): TRACE: action_result = self.dispatch(request, action, action_args)
(nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.6/nova/api/openstack/wsgi.py", line 395, in dispatch
(nova.api.openstack): TRACE: return controller_method(req=request, **action_args)
(nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.6/nova/scheduler/api.py", line 334, in new_f
(nova.api.openstack): TRACE: return f(*args, **kwargs)
(nova.api.openstack): TRACE: TypeError: rescue() got an unexpected keyword argument 'body'
(nova.api.openstack): TRACE: