Any particular reason you have to use CMD, rather than using FSO?
something like (and this is off the top of my head, so there may be errors)
I am a loud man with a very large hat. This means I am in charge
Dim objFSO, srcFile
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set srcFile = objFSO.GetFile("C:\codigobar\cinta" & session("cinta") & "\codigo.txt")
Set srcFile = Nothing
Set objFSO = Nothing