What do you mean, Cem ? You cannot select the planks in the inventory, and then use them on the boat ?
Have you take the planks and then the nails very quickly ? Because, if yes, it's THE fatal bug of the game, as it's said in the instructions of the game (on our website and in the game menu).
Citation:
WARNING: don’t try to pick up two items one after the other too quickly, otherwise the inventory may no longer work, and you will have to quit the game! Make sure you wait a few seconds until the first object has disappeared from the yellow frame on the upper left of the screen, and only then pick up the second item.
If it is your problem, the only solution is to begin from an older save than the one you use

Oh, and for the last hot spot, it will be useful further in the game
