error 'FIle is already open' vb6 text file

I am trying to write (replace existing value) in column 3 (0, 1, 2) with string "ABC"
at the record where first field is Smith.

    Call WriteToTxt("TextFileName", 2, "Smith", "ABC")
--------

Public Sub WriteToTxt(strTable As String, intField As Integer, strFind As String, strReplace As String)
    Dim intFileHandle As Integer
    Dim intFileHandle2 As Integer
    Dim strRETP As String
    Dim FieldArray As Variant
    Dim found As Boolean

    found = False
    intFileHandle = FreeFile
    intFileHandle2 = FreeFile
    Open "C:\" & strTable & ".txt" For Input As #intFileHandle

*** error 'FIle is already open' in next line *******
    Open "C:\" & strTable & ".txt.tmp" For Output As #intFileHandle2 ' temp file  
    While Not EOF(intFileHandle)
        Line Input #intFileHandle, strRETP
        If Not found Then
            FieldArray = Split(strRETP, "|")
            If FieldArray(0) = strFind Then
                FieldArray(intField) = strReplace
                strRETP = Join(FieldArray, "|")
                found = True
            End If
        End If
        Print #intFileHandle2, strRETP
    Wend
    Close #intFileHandle
    Close #intFileHandle2
    Kill "C:\" & strTable & ".txt" ' delete original
    Name "C:\" & strTable & ".txt.tmp" As "C:\" & strTable & ".txt" ' rename temp file
End Sub

How can I correct it?

Thanks.