Ack! Major screw up!
First, your mistakes (not being mean, just letting you know so you don't repeat them)
1) Yes, Kilz2 was a mistake. It is not worth the can it is packed in for precisely the reason you have discovered. You should have used a quality primer, such as Sherwin's PrepRite 200 Latex or Ben Moore's Fresh Start. Just go to a real paint store (not big box) and ask for a high-quality new-drywall primer.
2) Using tape on a primed-only wall. Any minor bits of paint getting from your ceiling onto the wall would not be a big deal. There is no reason to protect walls you plan to paint while doing the ceiling.
3) Using tape at all for the wall/ceiling joint. Even if you were now painting the walls, and had already done your ceiling, what you should be doing is using a high-quality brush to "cut-in" the joints instead of relying on tape. (A 2 1/2" Angle-Sash from Purdy is a popular, easily-available choice.) The only places I use tape are on knobs, hinges, and wood-stained trim. Another common use is to protect baseboards from spatter. (I'm painting all my trim after doing the walls, so this doesn't apply to me personally.)
I think Frog Tape might be useful for doing things like painting stripes, but you just don't need it for routine ceiling, wall, and trim painting.
Okay, you have several things to do here:
1) Aggressively sand and scrape your walls to remove any failing primer. It will probably hold okay to the drywall compound. You wan't to remove everything that is loose, or it will fail later on.
2) Skim Coat the walls with a huge drywall knife (10" or so) and some slightly thinned pre-mix Joint Compound. This is to cure the inevitable texture defects left behind by the missing primer spots. (You may be able to skip this step if the scraper manages not to damage your wall, and you can feather-out the missing spots with sanding.)
4) Topcoat with a quality Bathroom paint, such as Zinsser Perma-White, Sherwin's Bathroom paint, or (at SlickShift's suggestion) Ben Moore Aura.
If you can, hold off on any long, hot showers for a week before and after. All that steam can really mess up paint. Also, I would at least triple the drying times on the can.