Can't add or open Premiere file at all in Media Encoder

I've been working on a Premiere Pro Beta file today on a new Silicon Macbook Air, and when I try to export with Media Encoder I can't add the file to the queue at all. I've included a screenshot of the error message that I receive.

Steps to reproduce:
    1. ...
 
Result: ...
Expected: ...
 
System info
    Application: Adobe Media Encoder (Beta) v14.9.0.25
    OS: macOS v10.16.0, RAM: 16.00 GB, CPUs (logical): 8