New VBA procedure; error message

This is an example of a message presented in the event of an error being raised in the ‘NEW_Procedure’ procedure.
Please edit to suit your requirements.
Author: michael@excelexperts.co.uk

Sub errortrap(strMod As String, strSub As String, Optional iline As Integer)

    Dim linenumbermsg As String

    If iline = 0 Then
        linenumbermsg = ""
    Else
        linenumbermsg = "Line" & vbTab & " :  " & CStr(iline)
    End If

    ActiveSheet.Activate
    Call MsgBox("An error has been detected in the following:" _
                & vbCrLf & "" _
                & vbCrLf & "Module" & vbTab & " :  " & strMod _
                & vbCrLf & "Sub" & vbTab & " :  " & strSub _
                & vbCrLf & linenumbermsg _
                & vbCrLf & "" _
                , vbInformation, "Warning")

End Sub