Does it is Possible to Erase & Write Sector 0 in LPC2214

Hi,

I am implementing a functionality of IAP in LPC2214, for start up I have written a simple code in which
I am able to ease Sector 0 & other Sectors as Well, but when I try to write any data on sector 0 then it is not written it shows all 0xFF 0xFF .............
But in all the sectors data has been written succesfully only if I comment the sector 0 ERASE & WRITE function...

I have selected the ARM Mode in keil.

Can any one let me know what is the reason why I am not able to write on sector 0 ?
what are the parameters that has to be taken care while writing on sector 0 ?

#include "FlashOS.H"
#define M8(adr) (*((volatile unsigned char  *) (adr)))
void IAP_download(void);
volatile int  ret;
unsigned char TempBuf[1024] = " CMS CMS CMS ";
static unsigned char TempBuf2[1024];
unsigned int Cnt;

void IAP_download (void )
 {
  unsigned long n;
  unsigned short Cnt;
  ret = Init(0, 48000000, 1);
  // Erase Sector 0
  ret |= EraseSector(0x00000000);

  for (Cnt = 0; Cnt < 1024; Cnt++)
  {
    TempBuf2[Cnt] = '*';
  }

ret |=ProgramPage(0x00000000,1024,(unsigned char*)
                                        TempBuf2 );

/* main Function */




int main(void)
{
 IODIR0 = 0xFFFFFFFF;
 IODIR1 = 0xFFFFFFFF;
 // #pragma ARM
 VICIntEnClr = 0xFFFFFFFF;
 IAP_download( );
 // #pragma thumb
 while (1);
}

/* FalshPrg.c*/
#define STACK_SIZE     64      // Stack Size

#define SET_VALID_CODE 1       // Set Valid User Code Signature

unsigned long CCLK;            // CCLK in kHz

struct sIAP {                  // IAP Structure
  unsigned long cmd;           // Command
  unsigned long par[4];        // Parameters
  unsigned long stat;          // Status
} IAP;

void IAP_Execute (struct sIAP *pIAP);

unsigned long GetSecNum (unsigned long adr) {
  unsigned long n;

  n = (adr >> 13) & 0x1F;
  if (n >= 24) {
    n -= 14;
  }
  else if (n >= 8) {
    n  = 8 + (n >> 4);
  }

  return (n);
}

int Init (unsigned long adr, unsigned long clk, unsigned long fnc) {
unsigned int Cntr;

  CCLK  =  (1049*(clk >> 10)) >>10;

  MEMMAP  = 0x01;

  for(Cntr=0; Cntr<50000; Cntr++);
  for(Cntr=0; Cntr<50000; Cntr++);
  return (0);
}

int UnInit (unsigned long fnc) {
  return (0);
}


int EraseChip (void) {

  IAP.cmd    = 50;
  IAP.par[0] = 0;
  IAP.par[1] = 16;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  IAP.cmd    = 52;
  IAP.par[0] = 0;
  IAP.par[1] = 16;
  IAP.par[2] = CCLK;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  return (0);
}

int EraseSector (unsigned long adr) {
   unsigned long n;
   unsigned int Cntr;

   n = GetSecNum(adr);

  IAP.cmd    = 50;
  IAP.par[0] = n;
  IAP.par[1] = n;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  for(Cntr=0; Cntr<50000; Cntr++);
  for(Cntr=0; Cntr<50000; Cntr++);
  IAP.cmd    = 52;
  IAP.par[0] = n;
  IAP.par[1] = n;
  IAP.par[2] = CCLK;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  for(Cntr=0; Cntr<50000; Cntr++);
  for(Cntr=0; Cntr<50000; Cntr++);

  return (0);

}


int ProgramPage (unsigned long adr, unsigned long sz, unsigned char *buf) {
  unsigned long n;
  unsigned int Cntr;

#if SET_VALID_CODE != 0
  if (adr == 0) {
    n = *((unsigned long *)(buf + 0x00)) +
        *((unsigned long *)(buf + 0x04)) +
        *((unsigned long *)(buf + 0x08)) +
        *((unsigned long *)(buf + 0x0C)) +
        *((unsigned long *)(buf + 0x10)) +
        *((unsigned long *)(buf + 0x18)) +
        *((unsigned long *)(buf + 0x1C));
        *((unsigned long *)(buf + 0x14)) = 0 - n;
  }
#endif

  n = GetSecNum(adr);

  IAP.cmd    = 50;
  IAP.par[0] = n;
  IAP.par[1] = n;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  for(Cntr=0; Cntr<50000; Cntr++);
  for(Cntr=0; Cntr<50000; Cntr++);

  IAP.cmd    = 51;
  IAP.par[0] = adr;
  IAP.par[1] = (unsigned long)buf;
  IAP.par[2] = 1024;
  IAP.par[3] = CCLK;
  IAP_Execute (&IAP);
  if (IAP.stat) return (1);

  for(Cntr=0; Cntr<50000; Cntr++);
  for(Cntr=0; Cntr<50000; Cntr++);
  return (0);
}