The Apple Bonjour library is required to make the server pair automatically with the app, so that you won’t have to use the QRCode to pair it, and it’s already included in the Barcode To PC installer.

This error can be caused by these two reasons:

1. You don’t have the Apple Bonjour library installed
2. The Bonjour service is not started

To fix the issue:

1. Try to run the Barcode To PC installer again as administrator (it should install Apple Bonjour for you)
2. In case it doesn’t work you have to make sure that the service is running:

Type “Services” in the start menu and make you sure that Bonjour Service looks like this (Startup type: Automatic):

If it still doesn’t work reboot the system and check the service again