"Model class configModelConfig not found in file"

That's not an error coming from HikaShop.

It must be a plugin on your website which creates that error.

Could you try to add the code:

function getModel($name = '', $prefix = '', $config = array()) {
return false;
}

before the code:
function authorise($task){
return $this->authorize($task);
}

in the file adminitrator/components/com_hikashop/helpers/helper.php ? That will override the joomla model loading for controllers and that should avoid that another plugin try to load a non existing model.