Finals, finally, and final

My class went well this semester. However, I had several struggling students at the end of the semester. So, I spent a great deal of time reviewing material with the class for the final. After 3 long hours, I felt fairly confident the students were on the right track. However I was headed for finals hell. I had my first academic catastrophe. After working on a comprehensive, fair final for over a week, I downloaded the product and presented it to the class. After approx 15 minutes, someone asks, "Where are questions 15 - 30?" Then a little later, "Why are there two questions 42, 43, and 44?" I had erroneously copied the rough draft of the final. Subsequently the students earned 18 free questions and I earned a really red face.