I put it into recovery mode, and restored to ASUS stock (still rooted). The tablet booted fine and signed in to Google Play and accessed the web, but wouldn't download any files from play or from Goo.IM. I downloaded other versions of CM11 and tried going into recovery to flash them and got the same failure message. Occassionally, TWRP will give me a message saying my root permissions are incorrect and to repair them. When I repair them, it goes back to the reboot cycle and I have to restore to stock again.
I've since updated TWRP to 18.104.22.168 and uninstalled/reinstalled SuperSU. Through Titanium Backup, I restored the market links without any effect. I've also run the motochopper root utility to try and fix my root permissions. That has allowed me to successfully flash CM11, but when I boot it sticks on the CM splash screen with the arrow continually circling around. I've sat and waited for 30 minutes without any progress, so I don't think it's a matter of letting it figure itself out on the initial boot.
Any ideas? Thanks in advance for any help you can provide.