Wallpaper and Wallcoverings - Wallpapering on old plaster

I have tried to wallpaper over the old plaster on an outside wall that probably isn't insulated. The wall feels warm to the touch. I have sealed the walls since I wasn't sure what type of paint was used under the old wallcovering. However, the glue on the prepasted wallpaper that I am hanging is not drying. Any suggestions.

How long has it been since it was hung? Plaster walls have a significantly longer dry time than drywall. What was used as a primer?

Thanks for the help on the plaster walls. Maybe I should wait another day to see what happens. The primer I used I believe was called Shield.

Are you hanging over old wallpaper? If so, it will take a long time to dry because you are encapsulating wet adhesive between to vinyl layers. If not, wallpaper can take a while to "dry" depending on the humidity levels in your home. Use your heating/cooling systems to aid in the drying process. Heat and A/C both work humidity out of your home and I always insist on the use of the climate control system to aid in the drying process. That and I like to be comfortable when I work! ;) It's amazing how many people freeze in the winter and burn up in the summer........

If its a vinyl coated paper, and the wall in question is an outside wall, it could take up to a week or two to fully dry out. Wait and see what happens.

In our new 75 yr old house there are cracks in the coved living room ceiling. The walls are plaster with a few cracks, but the ceiling looks like tears in paper. There are veins all through the ceiling. Keeping with integrity of the house, what is the best way to repair the veins, only 2 have actually cracked through? Can I just open up the veins and apply a joint compound, or should I replaster the whole ceiling so it's seamless?

The answer to that depends on how much time/$$$ your budget will allow, or how good you want it to look.