OMG I feel your pain. I have had that happen several times and it is very very frustrating. My immediate thought is "What did I do wrong" but many times its not something I did wrong. Before this past christmas I was making a christmas tree skirt for my sister in law - my mom found me a wonderful pattern on the internet, printed it out and even cut the templates for me. I went out and took hours picking just the right fabrics. It was put together in three sections, inner piece of the pie, middle and outer section then you put the pieces of pie together to make the circle. Well, when I went to put the 3 sections together (with curves) there was no way they were going together. I quadruple checked the pieces to mae sure they matched the templates. After wracking our brains we went back to the pattern. It turns out, the pieces in the middle and outter section were scaled to fit on an 8 1/2 x 11 sheet of paper and it was not obvious on the pattern that had been done. I had to put the whole thing away I was so frustrated. Here is a picture - it would have been a gorgeous tree skirt too.