My personal suggestion to you: Now you have code whether its written by you or someone else does not matter much. Decode your own program using flow chart. I hope that you know how to draw a flow chart. Spend your time to draw a complete flow chart (decode the program), just pick up a large sheet of paper and draw the flow chart based on the code you have pasted here in this forum. I am sure you will find the reason why your program does not work. In the past I hade decoded several programs written by someone else whom I never met, neither will never meet and modified to suit my need. The programs were as big as 10000 lines including all subroutines. The program did not have any manual and nothing else except a few published research papers based on the program. I taught that trick to my students who were doing Undergraduate, M.E. and Ph.D. works. I had to spend more time on the notations on the flow chart and less time on how to decode it. I mean once you know the relation between flow chart and program language, you can debug yourself. Its efficient from both perspective: time and effort. GP