Previously working tapewire won't provide power?

This is the first time I've ever electrified a dollhouse. I watched a ton of videos, read a ton of FAQs, and managed to run a working tapewire! I know, because I checked both with the tester, and I plugged in a socket, tested it with ALL my lights.

After I wallpapered the house, all of a sudden it doesn't work anymore, except for one socket on the first floor. I don't understand. I suppose it's possible that a brad loosened (?!), but I haven't any idea how to fix it.

In addition, I must be the biggest idiot in the world, because I can't seem to plug in any new sockets (into parts of the tapewire I KNOW have power), and get them to light the lights. I know the lights work (with the one socket). I know SOME of the tapewire has power. I am so frustrated!

I think my next dollhouse is going to be hardwiring, this is very annoying.

I found the solution to my own problem- hit the sockets in more deeply, even if you thought they were already good. Yep.