Ann, I downloaded you data and ran the buffer tool using your parameters on all the point layers and they all ran without problem. This suggests to me there is someting weird going on with your output location. Try creating a blank geodatabase and create the buffers in that, so don't use the C:\ESRIPress\GIST1\MyExercises\Chapter9\Tutorial9.gdb Also start with a fresh session of arcmap with just that one point layer loaded to avoid any spatial reference issues. Duncan
... View more