Posting here for posterity...
My $0.002 advice? Replace one thing at a time. For whatever reason, the system worked when connected to the old BOB. Given what it took to make it work with the C23 BOB, I don't know how it could. The 4 red flashes error is also misleading as the documentation describes it as "Phase Error" when in reality was the lack of "Auto Tunning".
I had tried the "flick dip switch #4 twice within a second" and never managed to do anything. It's tricky. But once you get it, the motors will whine in crescendo for a couple of seconds and then it's all done and it all works.
By the way, that ProTuner tool is bit wacky to get it going. It was written in Visual Basic using an ancient Chinese version of VB. Out of the box it didn't work and gave all kinds of gibberish error messages (I'm assuming in Chinese). Luckily I'm a pakrat and was able to find some 10-year-old copy of Visual Studio with VB 6 in it. I installed it, deleted all the Chinese VB DLLs from the ProTuner directory and once I run it again (this time using the newly installed English VB DLLs), I was able to see that a file named del.dls had some bogus data in it. I deleted it, restarted it and it finally worked. Well... and then I just stared at it as I had no clue what to do with it