OpenERP Server Error

Client Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/http.py", line 204, in dispatch
    response["result"] = method(self, **self.params)
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1132, in call_button
    action = self._call_kw(req, model, method, args, {})
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1120, in _call_kw
    return getattr(req.session.model(model), method)(*args, **kwargs)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 42, in proxy
    result = self.proxy.execute_kw(self.session._db, self.session._uid, self.session._password, self.model, method, args, kw)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 30, in proxy_method
    result = self.session.send(self.service_name, method, *args)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 103, in send
    raise xmlrpclib.Fault(openerp.tools.ustr(e), formatted_info)


Server Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/session.py", line 89, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/opt/openerp/server/openerp/netsvc.py", line 292, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/opt/openerp/server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File "/opt/openerp/server/openerp/osv/osv.py", line 188, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/opt/openerp/server/openerp/osv/osv.py", line 131, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/openerp/server/openerp/osv/osv.py", line 197, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/openerp/server/openerp/osv/osv.py", line 185, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/openerp/server/openerp/addons/base/module/module.py", line 495, in button_immediate_uninstall
    return self._button_immediate_function(cr, uid, ids, self.button_uninstall, context=context)
  File "/opt/openerp/server/openerp/addons/base/module/module.py", line 475, in _button_immediate_function
    _, pool = pooler.restart_pool(cr.dbname, update_module=True)
  File "/opt/openerp/server/openerp/pooler.py", line 39, in restart_pool
    registry = RegistryManager.new(db_name, force_demo, status, update_module)
  File "/opt/openerp/server/openerp/modules/registry.py", line 218, in new
    openerp.modules.load_modules(registry.db, force_demo, status, update_module)
  File "/opt/openerp/server/openerp/modules/loading.py", line 413, in load_modules
    pool.get('ir.module.module').module_uninstall(cr, SUPERUSER_ID, mod_ids_to_remove)
  File "/opt/openerp/server/openerp/addons/base/module/module.py", line 439, in module_uninstall
    ir_model_constraint._module_data_uninstall(cr, uid, constraint_ids, context)
  File "/opt/openerp/server/openerp/addons/base/ir/ir_model.py", line 532, in _module_data_uninstall
    WHERE cs.contype=%s and cs.conname=%s and cl.relname=%s""", ('f', name, model_obj._table))
AttributeError: 'NoneType' object has no attribute '_table'

when i uninstalled my module, it shows the above error. How can i solve this?