Of course I tried it and it works fine

'ShowCentered Me

'Load the Template
rtbCoverLetter.LoadFile "C:\Temp.txt"

'Replace words in brackets with variables
'rtbCoverLetter = Replace(rtbCoverLetter, "#Date#", strProposalDate)
'rtbCoverLetter = Replace(rtbCoverLetter, "#Chron_Number#", strCor_Reference_Number)
iPos = 1
staffCount = lstSelected.ListCount

For idIndex = 0 To staffCount - 1
rtbCoverLetter = Replace(rtbCoverLetter.Text, "Helen", _
***This where I changed staffCount for 1***
(lstSelected.List(idIndex)), 1, 1, vbTextCompare)
Next
'rtbCoverLetter = Replace(rtbCoverLetter, "#Reference#", strRef)
'rtbCoverLetter = Replace(rtbCoverLetter, "#Subject#", strTitle)
'rtbCoverLetter = Replace(rtbCoverLetter, "#ACOTR#", strACOTR)