Error: Object Reference not set to an instance of an object

[XML newbie: Urgent pls help!]

I am using VB.Net. My program is to connect to a remote IPAddress. Once, it
verifies the login information it should display the SessionID and enable
some button . I appreciate your help and thanku in advance

When I run the pgm , I get the error:
Can't parse login information. Object Reference not set to an instance of an
object. I have added the Try-catch in all my functions. In ParseLoginRespo nse
function, it catches the above exception.

I am inclding all the functions I am using below:

Private Function SendXmlRequest( ByRef xml As String)

Try
Dim xmpRequest As HttpWebRequest = WebRequest.Crea te(XmpUrl)

' Instantiate an XmlDocument object to avoid NullReference
exception

Dim xmlDoc As XmlDocument

xmlDoc = New System.Xml.XmlD ocument

'System.Xml.Xml Document(xmldoc = New System.Xml.XmlD ocument)
'Dim xmlDoc As XmlDocument = Nothing
'Dim xmlReader As XmlTextReader

'xmlReader = Nothing
xmpRequest.Meth od = "POST"
xmpRequest.Keep Alive = True

xmpRequest.Cont entType = "text/xml"

Dim writer As StreamWriter

writer = New StreamWriter(xm pRequest.GetReq uestStream())

writer.Write(xm l)

writer.Close()
'Send the request and get the response

Dim HttpWResponse As HttpWebResponse =
CType(xmpReques t.GetResponse() , HttpWebResponse )
'Console.WriteL ine("before sending status")
'Get the status and the headers
Dim iStatCode As Integer = HttpWResponse.S tatusCode

Dim sStatus As String = iStatCode.ToStr ing()
Console.WriteLi ne("Status: {0} {1}", sStatus,
HttpWResponse.S tatusDescriptio n.ToString())

Console.WriteLi ne("Request Headers:")

Console.WriteLi ne(xmpRequest)

Console.WriteLi ne("Response Headers:")

Console.WriteLi ne(HttpWRespons e.Headers.ToStr ing())
'feb15

If Not HttpWResponse Is Nothing Then

Dim XmlRead = New
XmlTextReader(H ttpWResponse.Ge tResponseStream ())

'Dim xmlDoc As XmlDocument

'xmlDoc = New XmlDocument

'Dim xmlDoc = New XmlDocument

xmlDoc.Load(Xml Read)

Return xmlDoc
Else

Console.WriteLi ne("try again")

End If
'Get the response stream

Dim strm As Stream = HttpWResponse.G etResponseStrea m()
'Read the Response stream

Dim encode As Encoding =
System.Text.Enc oding.GetEncodi ng("iso-8859-1")

Dim sr As New StreamReader(st rm, encode)

Console.WriteLi ne("Response: {0}", sr.ReadToEnd())

sr.Close()

'new feb13

'Dim doc As New XmlDocument

'doc.Load(HttpW Response.GetRes ponseStream())

'doc.Save(Conso le.Out)

'end

HttpWResponse.C lose()
'Read the response stream

'Dim sr As StreamReader = New StreamReader(st rm)

'Dim sText As String = sr.ReadToEnd()

'Console.WriteL ine("Response: {0}", sText)

'???Close the stream

'strm.Close()

'Clean up

'xmpRequest = Nothing

'HttpWResponse = Nothing

'MyCredentialCa che = Nothing

'myCred = Nothing

'strm = Nothing

'sr = Nothing

'Feb14

'If sStatus = 200 Then

'The Http Request/Response was successful, now we need to check
the XML that was returned for errors

'If Not RequestHasErrro rs(xmpRequest.r esponseRext) Then

'The overall request was successful so begin to parse the
response XML

'SendXmlRequest = xmpRequest.resp onseXml

'End If

'Else

'End If
'End If

'Else

'Call MsgBox("There was an error. ReadyState = " &
xmpRequest.read yState)

'End If

Catch ex As NullReferenceEx ception

MsgBox("Can't Request page" & vbCrLf & ex.Message)

End Try

End Function

Private Function RequestHasError s(ByRef xml As String) As Boolean

' Check for the high level error Xml in any response before

' trying to parse the results.

If InStr(xml, "<Response><Err or>") >= 1 Then

RequestHasError s = True

End If

End Function

Private Function ParseLoginRespo nse(ByRef loginDom As XmlDocument) As
Boolean

' See if the login was successful. If so, get the SessionID.

' Otherwise, log the error.

Try
ParseLoginRespo nse = False

' Setup the Dom to use XPath queries and also setup

' an Xml namespace prefix for use in the XPath queries.

'Call loginDom.setPro perty("Selectio nLanguage", "XPath")

'loginDom.setPr operty("Selecti onNamespaces",
"xmlns:ns='urn: schemas-tms:LoginRespon se'")

Dim filterDoc As New XmlDocument

'Feb14

'Instantiate an XmlNamespaceMan ager object

Dim nsmgr As XmlNamespaceMan ager

nsmgr = New XmlNamespaceMan ager(filterDoc. NameTable)

'Add the namespaces used to the XmlNamespaceMan ager.
nsmgr.AddNamesp ace("ns", "urn:schema s -tms:LoginRespon se")

Dim node As XmlNode

node = loginDom.Select SingleNode("ns: LoginResponse/ns:Status")

'node = New XmlDocument

If node.Value = "Success" Then

' The login was 100% successful so get the SessionID.

'new Feb 14

'If node Is Nothing Then

'for testing

Console.WriteLi ne("Login successful: " & node.Value)

node =
loginDom.Select SingleNode("ns: LoginResponse/ns:SessionID")

'Dim resultImport As XmlNode

'resultImport = filterDoc.Impor tNode(node, True)

'filterDoc.Appe ndChild(resultI mport)

'Return True

'g_SessionID = node.Value

ParseLoginRespo nse = True

'Console.WriteL ine("Login successful: " & node.Value)

'Feb14

Else

'The login was not 100% successful

node =
loginDom.Select SingleNode("ns: LoginResponse/ns:SystemMessag e")

Console.WriteLi ne("Login unsuccessful: " & node.InnerText)



End If

Catch ex As Exception

MsgBox("Can't parse login information" & vbCrLf & ex.Message)

End Try

'Feb13()

'Return True

'Else

' The login was not 100% successful.

'node = loginDom.Select SingleNode("ns: LoginResponse/ns:SystemMessag e")

'Console.WriteL ine("Login unsuccessful: " & node.text)

'End If

'Feb13

'loginDom = Nothing

'node = Nothing

End Function



End Class