Create fleet vehicle contract : backtrace error

When creating a contract for a vehicle in a fleet the system issues a backtrace

Server Traceback (most recent call last):
  File "/var/openobject-server/hsd-7.0/web/addons/web/session.py", line 87, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/var/openobject-server/hsd-7.0/server/openerp/netsvc.py", line 281, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/var/openobject-server/hsd-7.0/server/openerp/service/web_services.py", line 603, in dispatch
    res = fn(db, uid, *params)
  File "/var/openobject-server/hsd-7.0/server/openerp/osv/osv.py", line 169, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/var/openobject-server/hsd-7.0/server/openerp/osv/osv.py", line 123, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/var/openobject-server/hsd-7.0/server/openerp/osv/osv.py", line 179, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/var/openobject-server/hsd-7.0/server/openerp/osv/osv.py", line 166, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/var/openobject-server/hsd-7.0/server/openerp/addons/base/res/res_partner.py", line 403, in name_get
    name = record.name
  File "/var/openobject-server/hsd-7.0/server/openerp/osv/orm.py", line 486, in __getattr__
    raise AttributeError(e)
AttributeError: 'Field name not found in browse_record(res.partner, 9)'

The last line contains the ID of the user logged in, which sounds wrong.