vb 向服务器发送数据，返回“不能解析您的提问，提问参数为空”是什么原因？

向搜搜问问服务器发送提问内容，返回“不能解析您的提问，提问参数为空”。
截获发送的数据是（UTF8）：{"userId":,"":"庣绛犳按","title":"鐢佃剳鐪嬩箙浜嗭紝鐪肩潧鏈夌偣绾紝濂借薄鏈夋矙瀛愶紝鎬庝箞鍔烇紵","content":"鏈変粈涔堝ソ鏂规硶","categoryId":553648128,"anonymous":true,"orig":1001,"modify":false,"origtmpid":0,"origtablename":"","synctwitter":false,"agreeNoFree":false}

不知道是哪出问题，哪位高手帮忙看看？

代码如下：
        '连接服务器
        If Winsock1.State <> 0 Then Winsock1.Close
        Do While Not Winsock1.State = 0
            DoEvents
        Loop
        Host = "wenwen.soso.com"
        Winsock1.RemoteHost = Host
        Winsock1.RemotePort = 80 'WEB服务器端口
        Winsock1.Connect
        Do While Not Winsock1.State = 7
            DoEvents
        Loop
            '发送登录请求
        'Dim strCommand As String
        'Dim ContentLength As Integer
        Dim PostData As String
        CategoryId = 559087616
        PostData = Replace("{""userId"":" & Text1.text & ",""userName"":""" & Nick & """,""title"":""" & UnicodeToUTF8(Text4.text) & """,""content"":""" & UnicodeToUTF8(Text5.text) & """,""categoryId"":" & CategoryId & ",""anonymous"":true,""orig"":1001,""modify"":false,""origtmpid"":0,""origtablename"":"""",""synctwitter"":false,""agreeNoFree"":false,""vcode"":""code""}", vbCrLf, "")
        ContentLength = Len(PostData)
        Head = "POST /z/api/ask/submit?format=json HTTP/1.1"
        strCommand = Head + vbCrLf
        strCommand = strCommand + "Accept: */*" + vbCrLf
        strCommand = strCommand + "Accept-Language: zh-cn" + vbCrLf
        strCommand = strCommand + "Referer: http://wenwen.soso.com/z/Ask.e" + vbCrLf
        strCommand = strCommand + "Content-Type: application/json; charset=UTF-8" + vbCrLf
        strCommand = strCommand + "Accept-Encoding: deflate" + vbCrLf
        strCommand = strCommand + "User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; QQDownload 718; .NET4.0C; .NET4.0E)" + vbCrLf
        strCommand = strCommand + "Host: " + Host + vbCrLf
        strCommand = strCommand + "Content-Length: " + str(ContentLength) + vbCrLf
        strCommand = strCommand + "Connection: Keep-Alive" + vbCrLf
        strCommand = strCommand + "Cache-Control: no-cache" + vbCrLf
        strCommand = strCommand + "Cookie: " + Cookie + vbCrLf
        strCommand = strCommand + vbCrLf
        strCommand = strCommand + PostData & vbCrLf
        Winsock1.SendData strCommand

补充：VB ,  网络编程