I gave in and read the manual. I would have saved myself a heck-of-a-lot of angst if I had done that to start with. There's nothing wrong with the machine -- it was all me.
To finish the blanket I followed an excellent tutorial I found on happythings, and kept things as simple as possible. The final product is a mash of fabrics I liked, but that don't really go well together, is a bit small, and a bit wonky, but Miss M loves it.
To keep things fair, and because I now knew how to make a quick blanket, I also made a super-simple one for my boy. His is incredibly comfy, with t-shirt material on one side, and super-soft flannel on the other.