Just paste this source code into a module called basStrings and include it in your project.
'----------------------------------------------------------------------
'
' Module Name: basStrings
' Written By: C&D Programming Corp.
' Create Date: 11/98
' Copyright: Copyright 1998 by C&D Programming Corp. Source
' code may not be reproduced except for use in a
' compiled executable. All rights reserved. If
' you would like to reprint any or all of this
' code please email us at info@codeoftheweek.com
'----------------------------------------------------------------------
Option Explicit
'
' This function works just like Instr, but it searches
' from the end of the string instead of the beginning
'
Public Function ReverseInstr(sStringToSearch As String, _
sStringToFind As String, _
Optional Compare As VbCompareMethod = vbBinaryCompare) As Long
Dim bDone As Boolean
Dim lStart As Long
Dim lLastPos As Long
lStart = 1
lLastPos = 0
bDone = False
While Not bDone
lLastPos = InStr(lStart, sStringToSearch, sStringToFind, Compare)
If lLastPos <> 0 Then
Debug.Print Mid(sStringToSearch, lLastPos) & " " & lStart & " " & lLastPos
lStart = lLastPos + 1 ' start searching just past where the string was found
Else
lLastPos = lStart - 1 ' set the last position sStringToFind was found
bDone = True ' we are done since lLastPos was zero which means
' the sStringToFind has no more matches.
End If
Wend
ReverseInstr = lLastPos
End Function