Do I Need A New Application ID For Each Installation?

We have a developer license and application ID which we have used to create a connector that pulls data from an ERP into Sage 50. It runs as a windows service. It has worked well on all our development boxes. Yesterday, we tried to install the windows service on our customer's server but our installer failed. After hours of experimenting, I decided to mangle our application ID in our code and discovered that our installer also started failing on our development boxes. Do we need another application ID for our customer's installation? They have a multi-user license.