An unhandled exception of type 'system.indexoutofrangeexception' occurred in windowsapplication1.exe additional information: index was outside the bounds of the array.

dim ECUData(27) as integer
dim RXArray(27) as integer

Private Sub Receiver(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs) Handles COMPorts.DataReceived
        If COMPorts.IsOpen = False Then
            COMPorts.Open()
        End If
        Dim RXByte As Byte

        RXCnt = 0
        Do

            RXByte = COMPorts.ReadByte

            RXArray(RXCnt) = Chr(RXByte) ' Convert each byte to two hexadecimal characters
            RXCnt = RXCnt + 1
            ECUData(RXCnt) = RXByte  <---------Getting Error in This Line
        Loop Until (COMPorts.BytesToRead = 0) ' Don't return if more bytes have become available in the meantime
        '----- End of communication protocol handling -------------------------------------------------------------
        Me.Invoke(New MethodInvoker(AddressOf Display)) ' Start "Display" on the UI thread
    End Sub