All pieces contain face mapping errors. Using the Repetier software for 3D printing, I have opened each STL file (piece by piece). When doing so, an icon appears (wrench). By clicking on this icon, the file is automatically repaired. It is valid for most of all pieces, except for ten that do not fixed it.
In the picture you can see the composition of two pieces (T83 & T101) that I have printed on plastic PLA type, to demonstrate the explained, and how the pieces fit perfectly together, including the original ones. The holes have to be filed a little.