vb6.0下post不成功，问题在哪

POST http://testgetqq.5d6d.com/post2884.php?action=reply&fid=2&tid=1&extra=page%3D1&replysubmit=yes&infloat=yes&handlekey=fastpost&inajax=1 HTTP/1.1
Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-powerpoint, application/vnd.ms-excel, application/msword, application/x-ms-application, application/x-ms-xbap, application/xaml+xml, application/QVOD, application/QVOD, */*
Referer: http://testgetqq.5d6d.com/thread-1-1-1.html
Accept-Language: zh-cn
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 2.0.50727; .NET CLR 4.0.20506; .NET CLR 1.1.4322)
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
Host: testgetqq.5d6d.com
Content-Length: 64
Proxy-Connection: Keep-Alive
Pragma: no-cache
Cookie: Hm_lpvt_19a7cf164294dff4a56c7490c27fa037=1296108833578; Hm_lvt_19a7cf164294dff4a56c7490c27fa037=1296104837250; lzstat_uv=1382737103318362446|1153300; i0B_sid=pfyEn7; __utma=25581497.1327961632.1296103548.1296103548.1296103548.1; __utmz=25581497.1296103548.1.1.utmcsr=rxhy.5d6d.com|utmccn=(referral)|utmcmd=referral|utmcct=/error.htm; i0B_visitedfid=2; i0B_uc_uid=0; smile=1D1; cdb_cookietime=2592000; cdb_fid2=1296106312; cdb_sid=0tL80H; cdb_auth=ONe%2B4HW%2B8Iqw54rdUa7G7Vsf6I9l4%2BI%2BgIFISgHjOE%2BVKrBntY17pKCDhJsofC1D7clbBIkhydmDDR2gMW9luD6lZeYRA4AbgBzuU%2FFmdl8M8r7Kpg6a64HT%2BKYT7h8FGp; cdb_uc_uid=43639755; cdb_f9fdfc0cb58188b3e86183f25e6719b4=3; cdb_oldtopics=D1D; cdb_2240b38e68bef81252c7a8853258971e=1; checkpm=1formhash=eee1e0931296108815&subject=&usesig=0&message=3788888777登陆问题已解决，就是发贴有问题    Set XMLHTTP = CreateObject("Microsoft.XMLHTTP")
    GetUrl = " http://testgetqq.5d6d.com/thread-1-1-1.html"
    XMLHTTP.Open "GET", GetUrl, True
    XMLHTTP.send
    
    
    Do Until XMLHTTP.ReadyState = 4
      DoEvents
    Loop
    formhash = "formhash=" & RemoveHeadTail(XMLHTTP.ResponseText, "name=""formhash"" value=""", """ />")
    PostUrl = "http://testgetqq.5d6d.com/post2884.php?action=reply&fid=2&tid=1&extra=page%3D1&replysubmit=yes&infloat=yes&handlekey=fastpost&inajax=1"
    PostData = formhash & "&subject=&usesig=0&message=" & UTF8EncodeURI("3788888777") & " '"
    With XMLHTTP
        .Open "POST", PostUrl, True
        .SetRequestHeader "Content-Type", "application/x-www-form-urlencoded"
        .SetRequestHeader "Content-Length", Len(PostData)
        .send (PostData)
        Do Until .ReadyState = 4
          DoEvents
        Loop
        ReturnCode = .ResponseText