Dark Aeon HaksWoRMs HaksThe required worms haks are as follows, you do not need them all.
The Under sea = wrm_undersea
The Seasonal Forest= sf_ddstextures2, sf_ddstextures1, sf_maintileset
The placeables= wrm_placeablev1
Of course you already know that these files go in the hak folder in your nwn directory