My heart is with you on this, p6ril. I have experienced it more than once or twice when I was playing on v1.0. But solved it, you will. Just may take an awfully long time if you're not lucky.
I do hope that island event happens before your adept builders die out. I remembered I set 3 - 4 villagers on sorting out after that island event and they only managed to become adept builders. So may be it's best to set only 1 - 2 villagers on that task if your current bunch of adept builders have died out by then.
The less frustrating and painful way is to upgrade to v1.1 and start a new game. It's much easier to play and you should be able to achieve to what you have now in a shorter time if you play Easy game on Normal speed most of the time (pause it when you sleep though).
