trouble with the optimizing level settings

Never had this problem, but I think the optimization put all the instructions in a slightly different order to optimize the performance throughput. As a result, it may unknowingly messed up some instructions in your program that have to be carried out in an exact order.

There should be some instructions that you can use to prevent sections of your code from being optimised. If there is, you can use them to find out the sections of your code that can't be optimized.

Hope this helps.

Tony