VIRB Edit 5.2.0 Won't Stitch

I've got a VIRB 360 and was very excited that at last the Edit software will stitch 5K and 5.7K footage. This works on my old system, but my brand new editing rig, with a 16-core AMD Threadripper 1950X CPU in it, won't do this. It starts the process, then gives up and stops. This is really annoying because I bought the new editing system precisely so it would scream through encoding and tasks like stitching 360 footage. Any ideas why it won't work?