It's common to have some wall damage when removing old wallpaper, but it should be fixable with patching using joint compound. What's going on here? Is your husband not doing it properly? It may take more than one application for deeper spots, and then some sanding. Why are there lumps? Is too much going on at a time? Is a too-narrow joint compound knife being used?

We need a little more info to help...

It may be the sanding has not been done.

You can buy an inexpensive drywall sanding tool at a home improvement store. They are generally grey or black and have a handle and a clamp on each end for inserting the drywall sand paper. I use the mesh drywall sandpaper. It seems to do a better job for me than the solid paper.

The problem your having is loose paper on the drywall,caused by the wall paper not being sized correctly. Using a large drywall knife 10" or 12" inches aply a THIN!! coat of fast setting joint compound on the entire wall (while your doing this pick out any blisters that occure) when this coat hardens do it all over again. then lightly sand. (Its alot of work thats why people leave wallpaper up forever). You can do it dont give up.

pinesville makes some really good points. I forgot to mention that usually, when I've repaired walls that were gouged after wallpaper removal, there are some places I've had to use single edge razor blades and cut out the tattered edges of the wallboard facing so they don't stick up.

Fond memories of what I just went through this weekend. We have a similar situation and it is a lot of work, but if you want good looking walls you have to have some patience and a good eye. Heres what I do. Fill in gouges, bumps etc. Use a wide blade on very damaged or rough areas. Like handymac suggested - mesh paper does a really good job of sanding things down. Since I always miss spots or can't really see imperfections until I vaccum and clean the walls (like small pit spots are hard to see). I will usually prime after my first run. I know most people will think this is a wasted step at this point, but it works for me. Once I prime, I can more easily see what areas I need to go over. Since I usually prime white - I dye some compound and go back and touch up any spots that I missed the first time around. Then I sand the spots, spot prime and I am usually ready to go with the paint. I also have some bad inside corners and seams where the ceiling meets the walls. For larger errors I use compound and tape if I need to. For small imperfections I find that a very thin bead of caulk will often cover up small spots. Good Luck!

If the wall was never primed before the wall paper went up you will need to prime it before trying to repair the damaged paper layer of the drywall.
The water in joint compound will cause the edges of any tears to swell and make a lump that wil not go down. If you sand it flat and apply another coat, more water soaks into the sanded paper area and it will swell again.
Setting compound can help sometimes, but if you are not experienced can be very hard to use. It sets in a specified time no matter how much water you add. Pre-mix drywall mud hardens by water evaporation, and can be dissolved again by adding water.

A coat of latex primer will help even out the surface color and make the defects more visible.
If the paper layer is torn or raised, cut it away with a razor knife.
Spot prime the area again.
Use a 5 inch or 6 inch drywall taping knife and joint compound to spread a smooth layer over the spot. Do not spend too much time trying to get it perfect. Dips are better than bumps.

After 24 hours, take the knife and lightly 'scrape' over the repairs. The new compound is dry, but even dried compound is not very hard. With the knife almost parallel to the surface run it over the repairs. Any slightly raised areas of bumps will be cut away.
If the compound area is large or very rough, it might take a few passes to smooth it down.
When all the bumps and nibs are down flat again, apply another coat of compound, spreading it out at least 3 inches away from the edge of every spot.
It takes practice to smooth the drywall mud out without a lot of bumps and gouges.
Work a little harder on this second coat.

When it dries you can run the knife over it again for any larger lumps, and then use a sanding screen to smooth out smaller bumps.
If you want to try you can also Âwet sandÂ. This uses a sponge to apply water to soften the compound and than gently wipe it smooth. Grout sponges (round corners) work pretty well for this.

Keep applying compound, and scrapping/sanding until the surface is as smooth as you want.
Spot prime it again to protect the patches.

My problem has not been getting the wall smooth, but rather to get it to match the existing drywall -which is not perfectly smooth. Where we have had to patch and then paint - you can tell where we patched b/c that surface is perfectly smooth. How do you fix that problem? We tried spraying on that texture stuff (in a can, looks a bit like that fake snow we used to spray on our windows at Christmastime) -but that was a mess and just looked like we had thrown cottage cheese at the wall :( Now that we're getting ready to put the house on the market we really need to make it look right - any suggestions?

Is the wall textured or are you looking at roller stipple from painting?
There are a number of ways of texturing walls. You need to igure out what the tesxture is (spray, sponge rolled, spray and knock down, broom, brush).

I drywalled my bathroom and the spackled was unfortunately caked on to the point that there are mounds of sanded spackle. I have tried and tried to sand it down to smooth it out with the drywall, but nothing seems to work. If I sand too much either the tape becomes exposed, the hole I was trying to cover shows, or the screw is exposed. I got it down to what I thought was decent, but found out after my first coat of paint that "decent" isnt where I wanted to be. Now I have a good looking wall except for areas that now have large bumps and lumps showing throught the paint. HELP PLEASE! Is there anything I can do to get these bumps and lumps to vanish and give me the smooth wall I had hoped for?