Hi, ktbear. Occasionally you can get a reaction between wallpaper glue residue and paint. Washing with TSP would have helped and priming with a good stain killer like B-I-N or Kilz would have been better. It doesn't matter that it was oil on oil, you still want a good primer/sealer. I think that you should go back to that step--a coat of one of the primers listed and I like B-I-N better--and then another coat of white.
Be sure that you have a window open when you put on the primer. It is alcohol based and the fumes can get to you. Also you want to stay far away from sources of ignition like your furnace, water heater, stove pilots and electric motors. Having great ventilation is the best thing.