Weird. After flashing to a clean 36-5 image because I couldn't get my rotation-enabled N800 to even recognize the SSU update, Adblock and User Agent Switcher are now installed and working perfectly for me. One thing I've noticed: Adblock's Chrome config page didn't display properly until I changed Microb's View,Encoding setting to Latin. YMMV.

I have not attempted to update adblock via the Components screen yet; considering that's what broke it last time around, let sleeping dogs lie sez I...

Hope this helps someone...