DELPHI截取网络数据包

DELPHI截取网络数据包 Delphi / Windows SDK/API
http://www.delphi2007.net/DelphiNetwork/html/delphi_20061218101640102.html
用Delphi和wincap包中PacketReceivePacket函数接包时出现内存泄漏。  
  这是扫描什么原因？  
  var  
  recvbuf:   array[0..1024*250   -   1]   of   char;  
   
  if   not   PacketSetBuff(lpAdapter,250*1024)   then  
  begin  
          ShowMessage(Format('PacketSetBuff   Error:   %d',[GetLastError()]));  
  exit;  
  end;  
   
  if   not   PacketSetReadTimeout(lpAdapter,1)   then  
  ShowMessage('Warning:   Unable   to   set   the   timeout');  
   
      lppacketr   :=   PacketAllocatePacket();  
  if   lppacketr   =   nil   then  
  begin  
  ShowMessage(Format('PacketAllocatePacket   receive   Error:   %d',[GetLastError()]));  
  exit;  
  end;  
   
  PacketInitPacket(lppacketr,@recvbuf,sizeof(recvbuf));  
   
  while   true   do  
  begin  
                        if   not   PacketReceivePacket(lpAdapter,lppacketr,true)   then   exit;  
                    end;    
 

用Delphi和wincap包中PacketReceivePacket函数接包时出现内存泄漏。  
  这是什么原因？