you will need to use the
LastDateModified property of the file.
you can get this by creating a ref to a file object.
If you stick with a simple vbscript which is always running you will need a nasty loop in it, something like
Do
Wscript.Sleep 60000
Wscript.Sleep 60000
Wscript.Sleep 60000
Wscript.Sleep 60000
Wscript.Sleep 60000
'im sure the 60000 is probably wrong
'5 mins has elapsed do the check
If DateDiff(n, aFile.DateLastModified, Now()) > 29 Then
'do something, send email?, write to eventlog?
End If
Loop