La modifica mi sembra semplice ... comunque

codice:
Const ForReading = 1
Const ForWriting = 2
Dim fso, i
Set fso = CreateObject("Scripting.FileSystemObject")
Set ts = fso.OpenTextFile("c:\filein.txt", ForReading)
s = ts.ReadLine
ts.Close
Set ts = fso.OpenTextFile("c:\fileout.txt", ForWriting, True)
for i=1 to len(s) step 26
ts.WriteLine Mid(s, i, 26)
next
ts.Close