LPC2389 IAP problems

Hi,
I'm using LPC2378,Fcclk=57.6MHz, Fcco=288MHz.
I have 2 problems.

Problem 1:
Cannot execute two IAP functions at a time.

IAP_Command(PREPARE_SECTORS, SECTOR_27, SECTOR_27,0,0);

works and returns a zero
but

IAP_Command(ERASE_SECTORS,SECTOR_27,SECTOR_27,57600,0);

will not work in conjunction with the above function.The program aborts/crashes.

If I execute only

IAP_Command(ERASE_SECTORS,SECTOR_27,SECTOR_27,57600,0);

then it will return status code 9 (Sectors not prepared for write operation)

Problem 2:
If I execute

IAP_Command(COPY_RAM_TO_FLASH,dest_flash_addr,source_ram_addr, 265, 57600);

after

IAP_Command(PREPARE_SECTORS, SECTOR_27, SECTOR_27,0,0);

then it will return status code 0x0D which does not exist.

Can anyone tell me what/where is the problem.
Is there any code reference anywhere on the web that clearly describes step by step the IAP programming procedure?

Thank you in advance for all the help.

Pinto.