Try
Dim xmlDoc As New XmlDocument()
xmlDoc.Load("D:\\s2.xml")

Dim nodeSource As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/source")
Dim strSource As String = IIf((nodeSource IsNot Nothing), nodeSource.InnerText, String.Empty)
'Console.WriteLine("source: " + strSource)

Dim nodecalogiTransactionRef As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/calogiTransactionRef")

Dim strcalogiTransactionRef As String = IIf((nodecalogiTransactionRef IsNot Nothing), nodecalogiTransactionRef.InnerText, String.Empty)
'Console.WriteLine("calogiTransactionRef: " + strcalogiTransactionRef)

Dim nodedocumentId As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/documentId")
Dim strdocumentId As String = IIf((nodedocumentId IsNot Nothing), nodedocumentId.InnerText, String.Empty)
'Console.WriteLine("documentId: " + strdocumentId)

Dim nodefinancialId As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/financialId")
Dim strfinancialId As String = IIf((nodefinancialId IsNot Nothing), nodefinancialId.InnerText, String.Empty)
'Console.WriteLine("financialId: " + strfinancialId)

Dim nodetransactionId As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/transactionId")
Dim strtransactionId As String = IIf((nodetransactionId IsNot Nothing), nodetransactionId.InnerText, String.Empty)
'Console.WriteLine("transactionId: " + strtransactionId)

Dim nodesubTransactionId As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/subTransactionId")
Dim strsubTransactionId As String = IIf((nodetransactionId IsNot Nothing), nodesubTransactionId.InnerText, String.Empty)

Dim nodechargeCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/chargeCode")
Dim strchargeCode As String = IIf((nodetransactionId IsNot Nothing), nodechargeCode.InnerText, String.Empty)

Dim nodelocationCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/locationCode")
Dim strlocationCode As String = IIf((nodetransactionId IsNot Nothing), nodelocationCode.InnerText, String.Empty)

Dim nodeaccountUser As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/accountUser")
Dim straccountUser As String = IIf((nodetransactionId IsNot Nothing), nodeaccountUser.InnerText, String.Empty)

Dim nodeamountInBC As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/amountInBC")
Dim strstramountInBC As String = IIf((nodetransactionId IsNot Nothing), nodeamountInBC.InnerText, String.Empty)

Dim nodebaseCurrencyCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/baseCurrencyCode")

Dim strbaseCurrencyCode As String = IIf((nodetransactionId IsNot Nothing), nodebaseCurrencyCode.InnerText, String.Empty)
Dim nodeforiegnCurrencyCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/foriegnCurrencyCode")

Dim strbaseforiegnCurrencyCode As String = IIf((nodetransactionId IsNot Nothing), nodeforiegnCurrencyCode.InnerText, String.Empty)

Dim nodeexchangeRate As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/exchangeRate")

Dim strbaseexchangeRate As String = IIf((nodetransactionId IsNot Nothing), nodeexchangeRate.InnerText, String.Empty)

Dim nodeaccountCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/accountCode")

Dim straccountCode As String = IIf((nodetransactionId IsNot Nothing), nodeaccountCode.InnerText, String.Empty)

Dim nodedateAndTimeBase As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/dateAndTimeBase")

Dim strdateAndTimeBase As String = IIf((nodetransactionId IsNot Nothing), nodedateAndTimeBase.InnerText, String.Empty)

Dim nodedateAndTimeLocal As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/dateAndTimeLocal")

Dim strdateAndTimeLocal As String = IIf((nodetransactionId IsNot Nothing), nodedateAndTimeLocal.InnerText, String.Empty)

Dim nodeaccountingDate As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/accountingDate")

Dim straccountingDate As String = IIf((nodetransactionId IsNot Nothing), nodeaccountingDate.InnerText, String.Empty)

Dim nodetransactingUser As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/transactingUser")

Dim strtransactingUser As String = IIf((nodetransactionId IsNot Nothing), nodetransactingUser.InnerText, String.Empty)

Dim nodeairportCode As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/airportCode")
Dim strairportCode As String = IIf((nodetransactionId IsNot Nothing), nodeairportCode.InnerText, String.Empty)

Dim nodemodeOfPayment As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/modeOfPayment")
Dim strmodeOfPayment As String = IIf((nodetransactionId IsNot Nothing), nodemodeOfPayment.InnerText, String.Empty)

Dim nodeformOfPayment As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/formOfPayment")
Dim strformOfPayment As String = IIf((nodetransactionId IsNot Nothing), nodeformOfPayment.InnerText, String.Empty)

Dim noderemarks As XmlNode = xmlDoc.SelectSingleNode("/transactionRequests/remarks")
Dim strremarks As String = IIf((nodetransactionId IsNot Nothing), noderemarks.InnerText, String.Empty)

Catch ex As Exception
MsgBox(ex.Message)
End Try