Break boards with hammer and chipper

[The chaser]

So, in your script:

void OnStart()
{
AddUseItemCallback("", "stone_hammer_chipper", "wooden_boards_block", "FUNC", true);
}

void FUNC (string &in asItem, string &in asEntity)
{
SetPropHealth("wooden_boards_block", 0);
///Other things (Remove item, etc)
}

You forgot a bracket in void OnGameStart()