I keep getting the error:  -2147024809  (80070057)  The parameter is
incorrect

Here is the XML text:

<?xml version="1.0" encoding="utf-8"?>
<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://
www.w3.org/2003/05/soap-envelope">
  <soap12:Header>
    <CMBHSAuthenticationHeader xmlns="http://www.dshs.state.tx.us/
cmbhs/">
      <CMBHSUserName>SClinician1</CMBHSUserName>
      <CMBHSPassword>D$h$..125</CMBHSPassword>
    </CMBHSAuthenticationHeader>
  </soap12:Header>
  <soap12:Body>
    <DownloadDocument xmlns="http://www.dshs.state.tx.us/cmbhs/">
      <Parameter>
        <ParentOrganizationNbr>2</ParentOrganizationNbr>
        <OrganizationNbr>3</OrganizationNbr>
        <FromDate>09/10/2009 4:03:11</FromDate>
        <ToDate>09/23/2009 10:05:05</ToDate>
        <DownloadType>1</DownloadType>
      </Parameter>
    </DownloadDocument>
  </soap12:Body>
</soap12:Envelope>

Here is my VBA code:

Private Sub Command2_Click()
    Dim XMLConnectString As String

    Dim XMLResponseText As String
    Me.Responsetext = ""
    XMLConnectString = Me.fld
    'Create the xmlhttp object
    Dim xmlhttp
    Set xmlhttp = CreateObject("Microsoft.XMLHTTP")
    'Open a connection and send a request to the server in the form of
an XML fragment
    Call xmlhttp.Open("POST", "http://cmbhstrn.dshs.state.tx.us/
cmbhswebservice/service/downloadservice.asmx", False)

    Call xmlhttp.send(XMLConnectString)


    'Create an xml document object, and load the server's response
    Dim xmldoc
    Set xmldoc = CreateObject("Microsoft.XMLDOM")
    xmldoc.async = False
    'Note: the ResponseXml property parses the server's response,
responsetext doesn't
    'xmldoc.loadxml (xmlhttp.responsexml)
    Me.Responsetext = xmlhttp.Responsetext
    Exit Sub
End Sub

The error line is:    Call xmlhttp.send(XMLConnectString)

Hopefully this is something simple.