Thank you very much for your comments, Miguel and John.
I have added some delays and tried with different delay time, but it doesn't help.
I have noticed that SigmaStudio generates different functions when using "export system files" compare to what is displayed in the capture window. the attached file shows what is displayed in the capture window.
With the "export system files", the five following fuctions are called.
SIGMA_WRITE_REGISTER_BLOCK( DEVICE_ADDR_IC_1, PROGRAM_ADDR_IC_1, PROGRAM_SIZE_IC_1, Program_Data_IC_1 );
SIGMA_WRITE_REGISTER_BLOCK( DEVICE_ADDR_IC_1, PROGRAM_ADDR_IC_1, PROGRAM_SIZE_IC_1, Program_Data_IC_1 );
SIGMA_WRITE_REGISTER_BLOCK( DEVICE_ADDR_IC_1, PROGRAM_ADDR_IC_1, PROGRAM_SIZE_IC_1, Program_Data_IC_1 );
SIGMA_WRITE_REGISTER_BLOCK( DEVICE_ADDR_IC_1, PROGRAM_ADDR_IC_1, PROGRAM_SIZE_IC_1, Program_Data_IC_1 );
SIGMA_WRITE_REGISTER_BLOCK( DEVICE_ADDR_IC_1, PROGRAM_ADDR_IC_1, PROGRAM_SIZE_IC_1, Program_Data_IC_1 );