Developing using Dexterity for Microsoft Dynamics GP 2015 or later

Today, I was contacted by a fellow Dexterity developer who was having trouble getting Dexterity for Microsoft Dynamics GP 2015 or later to run Dynamics.dic in Test Mode.
In this article, I will take you through the errors you could get and how to resolve them. Some of these you might know from previous versions, others are new to GP 2015 or later.
Part of the #Dexterity Development Environments Series. See Summary at end for quick list.
