CHttpfile->SendRequest发送字符串出错

用HTTP协议POST发送CHttpfile fileGet = pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_POST,"*****");  CString szHeaders = "Accept: */*\r\nUser-Agent: mozilla/4.0(compatible;msie 5.5; windows98)\r\nContent-Type: application/x-www-form-urlencoded\r\nConnection: Keep-Alive\r\n";fileGet->AddRequestHeaders(szHeaders);date =  "AA=BB&CC=DD&FF=GG";fileGet->SendRequest(NULL,0, date,strlen(date)+1);前几个发送是正常的,之后就会出现以下错误：   <HTML><HEAD>
<TITLE>501 Method Not Implemented</TITLE>
</HEAD><BODY>
<p>Method Not Implemented<br/>
</p>
<HR>
<ADDRESS>Apache/2.2.14 Server at 127.0.0.1 Port 80</ADDRESS>
请求解答：