booking Air New Zealand reward flights - tips?

have been trying to book a Business/ UC rewards flight on Air NZ - a companion airline - for January next year, (LAX to AKL) and not getting anywhere with the normal procedure: ring Virgin FC, give dates, wait a day, get rejected ('unconfirmed')... try other dates, wait day, get same result... repeat ad infinitum, etc.
HOWEVER, when I ring air NZ direct, and check availability for their own reward seats on the same dates, there is multiple availability. Any idea whats going on besides FC members being lower on the rung than Air NZ's own members? any ideas how to break this logjam and/or when those reward seats might get freed up to partners rather than reserved for their own f. flyers?
thanks.
HOWEVER, when I ring air NZ direct, and check availability for their own reward seats on the same dates, there is multiple availability. Any idea whats going on besides FC members being lower on the rung than Air NZ's own members? any ideas how to break this logjam and/or when those reward seats might get freed up to partners rather than reserved for their own f. flyers?
thanks.