SCHUTZEE: Two things: 1)Try flying on N6 instead---they have an interline ticketing with group Taca. If all else fails, break the LIM/CUZ flight out and book it separately. This will drive up the cost because it will no longer be treated as an online transfer but at least you will have a ticket.
MAUIGIRL: I find it hard to believe Taca Peru would "only have V class seats left". Most airlines sell out of the cheaper seats first, leaving the full Y for the last becuase they get the most revenue from it.