I'm beating my head against the computer.
Unlike with raw capture #5, QuickPar'ing the raw capture #4 RARs consistently fails with the message: "Failed: Could not allocate output buffer". This is supposedly caused by having too much memory available, so I tried running it with 1/2 of my 4GB in use, but it was still a no-go. Similarly, I tried running it with a minimum amount of memory in use and, as expected, it was a no-go.
>:-O