Fix error in Magento extension

Fix error in Magento extension


Job Description

I have extension installed on my Magento server.
It has a feature to show what vehicle the customer selected in their order. Please see below the instructions to have it show up which I have done.

The problem I have is after an upgrade of Magento, if a user has a vehicle selected it will cause the order screen to be blank, please check pic:

Can fix this on my test site then move fix to live site. (test site is not showing the extension properly so need to get it active there 1st)