just do what I said last time. burn some file to the disk (any file - just to create another session).
use nero (not express). With that disk in the burner, in multisession tab, choose "continue multisession disk". nero will list all the sessions on the the disk, click the older session (skip the last session)and burn.
use nero (not express). With that disk in the burner, in multisession tab, choose "continue multisession disk". nero will list all the sessions on the the disk, click the older session (skip the last session)and burn.