异步模式下 程序运行一段时间后错误

异步模式下 程序运行一段时间后异常！
我的程序：
unsigned char SendBuffer[4] = {0x02, 0x10, 0x81, 0x6c};
定时器里发送数据：  
  OVERLAPPED m_ossend;
  COMSTAT Cs;
  unsigned long nwrite;
memset(&m_ossend,0,sizeof(OVERLAPPED));
m_ossend.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
  unsigned char number = SendBuffer[0];
  DWORD dwErrorFlags;
  ClearCommError(HandleCom,&dwErrorFlags,&Cs);
  if (WriteFile(HandleCom, SendBuffer, number + 2, &nwrite, &m_ossend) == 0)
  {
  if(GetLastError()==ERROR_IO_PENDING)
{
WaitForSingleObject(m_ossend.hEvent,1000);
}
  }

线程里接受数据：
void __fastcall FR::Execute()
{

  while(!Terminated)
  {
  Synchronize(Receive);
  }
}
//---------------------------------------
void __fastcall FR::Receive()//数据接收
{
  static double count= 0;

  Form1->DisByteMemo->Text = count;
  count++;
  unsigned char ReceiveBuffer[512] = {0};
  unsigned long ReceiveBufferLength = 512;
  OVERLAPPED m_osRead;
  COMSTAT Cs;
memset(&m_osRead,0,sizeof(OVERLAPPED));
m_osRead.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);
  unsigned long nread;
  unsigned long Error;
  for (int i = 0;i < ReceiveBufferLength; i++)
  {
  ReceiveBuffer[i] = 0x00;
  }

  ClearCommError(HandleCom, &Error, &Cs);

  if (Cs.cbInQue > 0 )
  {
  int temp = min(Cs.cbInQue,ReceiveBufferLength);
  if(ReadFile(HandleCom, ReceiveBuffer, temp, &nread, &m_osRead) == false)
  {
  if(GetLastError()==ERROR_IO_PENDING)
{
WaitForSingleObject(m_osRead.hEvent,2000);
}
  }
  }
}

我在使用异步模式发送接受数据，开始的20分钟左右，发出数据和接收数据都正常。运行一段时间后，程序抛出异常，然后电脑像司机一样。求大侠给予指点。

------解决方案--------------------
只需定义一个就可以了，然后根据GetLastError函数的返回值进行判断。
像这样的问题最后去VC\MFC版块问，呵呵哪里解答的人会更多些，四处开花嘛