What did I do wrong?

I was trying to make steamed dumplings (recipe here). The filling came out really good. And I wrapped them up in wonton wrappers (well, egg roll wrappers, but, same stuff, right?), and I set them on one of those springy UFO-like expanding steamer things, over boiling water as noted in the directions. But the wrappers were a complete disaster. The tops got cooked pretty well (where I had smushed up the wrapper and sealed it), but the bottoms were soggy and stuck to both the bottom of the steamer and to the dumpling next to it. I couldn't get them off the steamer without ruining them. So I saved the filling and maybe will try again with a wrapper, but can anyone who has done this kind of thing successfully tell me how to do the steaming?