Calculo do CRC

[Calculo do CRC]

Bom dia pessoal, convertir essa função do C# para vba ele funciona perfeitamento no excel e access
porem estou tentendo usar ela no vb.net  editor VISUAL STUDIO 2013, aparece o erro conforme a imagem enexo, alguem consegue corrigir esse erro;
Function crc_ccitt_ffff(strParam As String) As String
        Const CRC_POLY_CCITT As Long = &H1021&
        Const CRC_START_CCITT_FFFF As Long = &HFFFF&
        Dim crc As Long, b() As Byte, c As Long, i As Long, j As Long
        Dim crc_tabccitt(0 To 255) As Long
        For i = 0 To 255
            crc = 0
            c = i * 256
            For j = 0 To 7
                If (crc Xor c) And 32768 Then
                    crc = (crc * 2) Xor CRC_POLY_CCITT
                Else
                    crc = crc * 2
                End If
                c = c * 2
            Next j
            crc_tabccitt(i) = crc
        Next i
            b = strParam
        crc = CRC_START_CCITT_FFFF
        For i = 0 To UBound(b) Step 2
            crc = (crc * 256) Xor crc_tabccitt(((crc \ 256) Xor b(i)) And 255)
            crc = ((crc \ 65536) * 65536) Xor crc
        Next i
        crc_ccitt_ffff = Hex(crc)
    End Function