I cann't delete any model whether has tag or not !!!

I have the same problem.
When insert new vehicle make is all ok, but when i try to delete a vehice make i got this error:

Warning: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->load() (linea 175 di /Volumes/Dati HDD/WebSites/AutoClubSite/includes/entity.inc).
Warning: array_flip(): Can only flip STRING and INTEGER values! in DrupalDefaultEntityController->cacheGet() (linea 388 di /Volumes/Dati HDD/WebSites/AutoClubSite/includes/entity.inc).

Someone has found the solution?
Thanks

I do not know if it's the right solution but it works for me.
I can not apply a patch and then I put the code here.
So:

• in "vehicle_make.module" go around line 576

function vehicle_make_delete($entity) {
    //entity_get_controller('vehicle_make')->delete($entity->make_id);
    db_delete('vehicle_make')
        ->condition('make_id', $entity->make_id)
        ->execute();
}

The same is with Vehicle Model:

• in "vehicle_make.module" go around line 602

function vehicle_model_delete($entity) {
    db_delete('vehicle_model')
        ->condition('model_id', $entity->model_id)
        ->execute();
  //entity_get_controller('vehicle_model')->delete($entity);
}