I create a module and when I uninstall it, I have the following error message.

How can I uninstall it without this error message?

Traceback (most recent call last): File "/usr/lib/pymodules/python2.7/openerp/http.py", line 470, in dispatch result = self._call_function(**self.params) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 294, in _call_function return checked_call(self.db, *args, **kwargs) File "/usr/lib/pymodules/python2.7/openerp/service/model.py", line 113, in wrapper return f(dbname, *args, **kwargs) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 291, in checked_call return self.endpoint(*a, **kw) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 638, in __call__ return self.method(*args, **kw) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 337, in response_wrap response = f(*args, **kw) File "/usr/lib/pymodules/python2.7/openerp/addons/web/controllers/main.py", line 1246, in call_button action = self._call_kw(model, method, args, {}) File "/usr/lib/pymodules/python2.7/openerp/addons/web/controllers/main.py", line 1234, in _call_kw return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs) File "/usr/lib/pymodules/python2.7/openerp/addons/base/module/module.py", line 499, in button_immediate_uninstall return self._button_immediate_function(cr, uid, ids, self.button_uninstall, context=context) File "/usr/lib/pymodules/python2.7/openerp/addons/base/module/module.py", line 479, in _button_immediate_function registry = openerp.modules.registry.RegistryManager.new(cr.dbname, update_module=True) File "/usr/lib/pymodules/python2.7/openerp/modules/registry.py", line 299, in new openerp.modules.load_modules(registry._db, force_demo, status, update_module) File "/usr/lib/pymodules/python2.7/openerp/modules/loading.py", line 403, in load_modules registry['ir.module.module'].module_uninstall(cr, SUPERUSER_ID, mod_ids_to_remove) File "/usr/lib/pymodules/python2.7/openerp/addons/base/module/module.py", line 443, in module_uninstall ir_model_constraint._module_data_uninstall(cr, uid, constraint_ids, context) File "/usr/lib/pymodules/python2.7/openerp/addons/base/ir/ir_model.py", line 521, in _module_data_uninstall model_obj = self.pool[model] File "/usr/lib/pymodules/python2.7/openerp/modules/registry.py", line 106, in __getitem__ return self.models[model_name] KeyError: u'formateur'

Thanks