Here's what I've concluded ... it is something in the SYS. I put 21893 in the Beta2 kitchen and still got the tweaks.cab error. So, I rebuilt with 21892 in the same kitchen with the same stuff and it boots and runs fine. I'm just going to give up on 21893 for now. Maybe tomorrow I will re-download the RC kitchen and put 21892 in it and see what it does. This just seems over my head right now.
Thanks to everyone who had an idea, though. I appreciate it.