Couldn't start nova-compute service due to sql error

I tried to install the newest version(2011.1~bzr592-0ubuntu0ppa1~maverick1) from ppa. But I couldn't start nova-compute service due to the following error.

Traceback (most recent call last):
 File "/usr/bin/nova-compute", line 44, in <module>
   service.serve()
 File "/usr/lib/pymodules/python2.6/nova/service.py", line 228, in serve
   x.start()
 File "/usr/lib/pymodules/python2.6/nova/service.py", line 86, in start
   self.binary)
 File "/usr/lib/pymodules/python2.6/nova/db/api.py", line 132, in
service_get_by_args
   return IMPL.service_get_by_args(context, host, binary)
 File "/usr/lib/pymodules/python2.6/nova/db/sqlalchemy/api.py", line
96, in wrapper
   return f(*args, **kwargs)
 File "/usr/lib/pymodules/python2.6/nova/db/sqlalchemy/api.py", line
247, in service_get_by_args
   filter_by(deleted=can_read_deleted(context)).\
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/query.py",
line 1496, in first
   ret = list(self[0:1])
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/query.py",
line 1405, in __getitem__
   return list(res)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/query.py",
line 1565, in __iter__
   return self._execute_and_instances(context)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/query.py",
line 1570, in _execute_and_instances
   mapper=self._mapper_zero_or_none())
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/session.py",
line 735, in execute
   clause, params or {})
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/base.py",
line 1157, in execute
   params)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/base.py",
line 1237, in _execute_clauseelement
   return self.__execute_context(context)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/base.py",
line 1268, in __execute_context
   context.parameters[0], context=context)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/base.py",
line 1367, in _cursor_execute
   context)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/base.py",
line 1360, in _cursor_execute
   context)
 File "/usr/lib/python2.6/dist-packages/sqlalchemy/engine/default.py",
line 288, in do_execute
   cursor.execute(statement, parameters)
 File "/usr/lib/pymodules/python2.6/MySQLdb/cursors.py", line 166, in execute
   self.errorhandler(self, exc, value)
 File "/usr/lib/pymodules/python2.6/MySQLdb/connections.py", line 35,
in defaulterrorhandler
   raise errorclass, errorvalue
sqlalchemy.exc.ProgrammingError: (ProgrammingError) (1146, "Table
'nova.services' doesn't exist") 'SELECT services.created_at AS
services_created_at, services.updated_at AS services_updated_at,
services.deleted_at AS services_deleted_at, services.deleted AS
services_deleted, services.id AS services_id, services.host AS
services_host, services.`binary` AS services_binary, services.topic AS
services_topic, services.report_count AS services_report_count,
services.disabled AS services_disabled, services.availability_zone AS
services_availability_zone \nFROM services \nWHERE services.host = %s
AND services.`binary` = %s AND services.deleted = %s \n LIMIT 0, 1'
('ubuntu7', 'nova-compute', False)

BTW, I used mysql as db server. I logged into mysql server, find there is no tables in db nova. I guessed something wrong in the installation.

Please tell me why.

Thank you.