Setting up nrf51 DK

Hi,

I am having trouble setting a stable working environment. I follow this post(https://rowley.zendesk.com/entries/79953939-Nordic-nRF51-Examples-and-CrossWorks) and added the Section Placement Macros. I can download program to the board and it runs. However, every time I disconnect or press reset button. The program on the board will no longer work. I am wondering what what did I do wrong? (I am using nordic SDK 8.0, also with Section Placement set to Flash_S120) Thanks.