I can not install new module, I receive this error message that appears. 
do you have a solution ?

OpenERP Server Error

Traceback (most recent call last): File "/home/odoo/src/odoo/saas-3/openerp/http.py", line 379, in _handle_exception return super(JsonRequest, self)._handle_exception(exception) File "/home/odoo/src/odoo/saas-3/openerp/http.py", line 398, in dispatch result = self._call_function(**self.params) File "/home/odoo/src/odoo/saas-3/openerp/http.py", line 235, in _call_function return checked_call(self.db, *args, **kwargs) File "/home/odoo/src/odoo/saas-3/openerp/service/model.py", line 114, in wrapper return f(dbname, *args, **kwargs) File "/home/odoo/src/odoo/saas-3/openerp/http.py", line 232, in checked_call return self.func(*a, **kw) File "/home/odoo/src/odoo/saas-3/openerp/http.py", line 562, in __call__ return self.method(*args, **kw) File "/home/odoo/src/odoo/saas-3/addons/web/controllers/main.py", line 1237, in call_button action = self._call_kw(model, method, args, {}) File "/home/odoo/src/odoo/saas-3/addons/web/controllers/main.py", line 1225, in _call_kw return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs) File "/home/odoo/src/odoo/saas-3/openerp/addons/base/module/module.py", line 427, in button_immediate_install return self._button_immediate_function(cr, uid, ids, self.button_install, context=context) File "/home/odoo/src/custom/trial/saas_trial/module.py", line 30, in _button_immediate_function res = super(ir_module_module, self)._button_immediate_function(cr, uid, ids, function, context=context) File "/home/odoo/src/odoo/saas-3/openerp/addons/base/module/module.py", line 474, in _button_immediate_function registry = openerp.modules.registry.RegistryManager.new(cr.dbname, update_module=True) File "/home/odoo/src/odoo/saas-3/openerp/modules/registry.py", line 247, in new openerp.modules.load_modules(registry.db, force_demo, status, update_module) File "/home/odoo/src/odoo/saas-3/openerp/modules/loading.py", line 341, in load_modules loaded_modules, update_module) File "/home/odoo/src/odoo/saas-3/openerp/modules/loading.py", line 244, in load_marked_modules loaded, processed = load_module_graph(cr, graph, progressdict, report=report, skip_modules=loaded_modules, perform_checks=perform_checks) File "/home/odoo/src/odoo/saas-3/openerp/modules/loading.py", line 175, in load_module_graph _load_data(cr, module_name, idref, mode, kind='data') File "/home/odoo/src/odoo/saas-3/openerp/modules/loading.py", line 116, in _load_data tools.convert_file(cr, module_name, filename, idref, mode, noupdate, kind, report) File "/home/odoo/src/odoo/saas-3/openerp/tools/convert.py", line 970, in convert_file convert_yaml_import(cr, module, fp, kind, idref, mode, noupdate, report) File "/home/odoo/src/odoo/saas-3/openerp/tools/yaml_import.py", line 937, in yaml_import yaml_interpreter.process(yaml_string) File "/home/odoo/src/odoo/saas-3/openerp/tools/yaml_import.py", line 873, in process self._process_node(node) File "/home/odoo/src/odoo/saas-3/openerp/tools/yaml_import.py", line 886, in _process_node self.process_python(node) File "/home/odoo/src/odoo/saas-3/openerp/tools/yaml_import.py", line 561, in process_python unsafe_eval(code_obj, {'ref': self.get_id}, code_context) File "/home/odoo/src/odoo/saas-3/addons/account/account_pre_install.yml", line 7, in <module> wiz = wizards.browse(cr, uid, ref('account.account_configuration_installer_todo')) AttributeError: 'bool' object has no attribute 'lower'

Ok