The Problem
With the upgrade to ProPresenter 7.15, there is an outstanding bug with the Companion module that causes an issue. You may see a Companion error when trying to use buttons that control ProPresenter, such as:
Cannot read property 'presentationName'
Or, the module in Companion will crash. You could also see an issue like this:
The bug has been reported to Companion and is a long standing one.
Solution
To fix this issue, in Companion go to your ProPresenter connection and change "Send Presentation Info Requests To ProPresenter" to "No". After changing, click "Save" to reconnect to ProPresenter. It may be helpful to restart the computer that Companion is running on.