Checkout success error

Hello

We have recently upgraded Openart to 2.3.0.2. When a user makes a purchase the process works correctly the only problem is this error message appears at the top of the page.

I have installed the latest vpmod, we are using Journal 2 theme.

Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no effect in
/var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php
on line 9Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no effect in
/var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 10Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no
effect in /var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 11Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no
effect in /var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 12Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no
effect in /var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 13Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no
effect in /var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 14Notice: Indirect modification of overloaded property ControllerCheckoutSuccess::$data has no
effect in /var/sites/a/my-website/public_html/vqmod/vqcache/vq2-catalog_controller_checkout_success.php on line 15

Does anyone know of a fix for this?

Looks like some of your extensions tries to modify $data variable and it does it in some weird way. Just open the mentioned file and take a look into mentioned lines. You'll get an idea, if you know some PHP. If you don't - copy these lines here.

Thank you for responding and I'm sorry for not replying sooner, I've been working on another Opencart website.
Here are the lines form 9 to 15:
$this->data['orderDetails'] = $this->model_checkout_order->getOrder($this->session->data['order_id']);
$this->data['orderProduct'] = $this->model_checkout_order->getOrderProduct($this->session->data['order_id']);
$this->data['orderProductOptions'] = $this->model_checkout_order->getOrderProductOptions($this->session->data['order_id']);
$this->data['orderDetails']['shipping_total'] = (isset($this->session->data['shipping_method']['cost'])) ? $this->session->data['shipping_method']['cost'] : 0;
$this->data['ga_conversion_id'] = $this->config->get('config_ga_conversion_id');
$this->data['ga_label'] = $this->config->get('config_ga_label');
$this->data['ua_tracking'] = $this->config->get('config_ua_tracking');

On OC 2.0 $this->data is replaced with $data.

Thank you. I'm a little unsure as to which file to edit.
The lines of code above don't appear in catalog/controller/checkout/success.php

hello,
i have problem, i want to sent a success msg after registrasion.how to set this in opencart 2.