Migrate data from 4.2 to 5.0

How would you go about this ?

I have tried simply starting the server with the databse but when I launch the client it crashes on me the moment I try to login on the client with this message :

red15@nightbrick:/tmp/client/bin$ ./openerp-client.py
Traceback (most recent call last):
  File "./openerp-client.py", line 152, in <module>
    win.sig_login()
  File "/tmp/client/bin/modules/gui/main.py", line 719, in sig_login
    log_response = rpc.session.login(*res)
  File "/tmp/client/bin/rpc.py", line 216, in login
    res = _sock.myreceive()
  File "/tmp/client/bin/tiny_socket.py", line 86, in myreceive
    raise Myexception(str(res[0]), str(res[1]))
tiny_socket.Myexception: ('ERROR: column "state" does not exist\nLINE 1: select * from ir_model where state=\'manual\'\n ^\n\nselect * from ir_model where state=\'manual\'', 'Traceback (most recent call last):\n File "/tmp/server/bin/netsvc.py", line 386, in run\n r = m(*msg[2:])\n File "/tmp/server/bin/service/web_services.py", line 328, in login\n res = security.login(db, login, password)\n File "/tmp/server/bin/service/security.py", line 29, in login\n cr = pooler.get_db(db).cursor()\n File "/tmp/server/bin/pooler.py", line 87, in get_db\n return get_db_and_pool(db_name)[0]\n File "/tmp/server/bin/pooler.py", line 49, in get_db_and_pool\n addons.load_modules(db, force_demo, status, update_module)\n File "/tmp/server/bin/addons/__init__.py", line 337, in load_modules\n load_module_graph(cr, graph, status, report=report)\n File "/tmp/server/bin/addons/__init__.py", line 294, in load_module_graph\n cr.execute(\'select * from ir_model where state=%s\', (\'manual\',))\n File "/tmp/server/bin/sql_db.py", line 69, in execute\n res = self.obj.execute(sql, p)\nProgrammingError: ERROR: column "state" does not exist\nLINE 1: select * from ir_model where state=\'manual\'\n ^\n\nselect * from ir_model where state=\'manual\'\n')

And when I just try to run the server with --update=all it hangs on me after following messages :

[Wed Nov 05 18:33:37 2008] INFO:init:addon:base:creating or updating database tables
Traceback (most recent call last):
  File "./openerp-server.py", line 134, in <module>
    pooler.get_db_and_pool(tools.config['db_name'], update_module=True)
  File "/tmp/server/bin/pooler.py", line 49, in get_db_and_pool
    addons.load_modules(db, force_demo, status, update_module)
  File "/tmp/server/bin/addons/__init__.py", line 337, in load_modules
    load_module_graph(cr, graph, status, report=report)
  File "/tmp/server/bin/addons/__init__.py", line 248, in load_module_graph
    init_module_objects(cr, m, modules)
  File "/tmp/server/bin/addons/__init__.py", line 221, in init_module_objects
    obj._auto_init(cr, {'module': module_name})
  File "/tmp/server/bin/osv/orm.py", line 1305, in _auto_init
    self._field_create(cr, context=context)
  File "/tmp/server/bin/osv/orm.py", line 354, in _field_create
    if cols[k][key] != vals[key]:
KeyError: 'select_level'