Need help about weapons config

[panda]

Questions about Natural Weapons:
I have problems implementing a natural weapon:

1) I can't find a way to remove the reach in the statblock
2) I would like to change change "one creature" target to "one creature directly underneath the ..."

[Hollis]

Set the wReach field to 0.

Have you tried setting the wTarget field?

[panda]

If i put 0 in wReach it still display reach 0 ft in the statblock.
If i change the wTarget it is ignored because the tag is set to onecreature. If I remove the tag and set wTarget it give a compilation error :
Hero Lab was forced to stop compilation after the following errors were detected:
Thing 'r5CMMPierc' - Undefined field 'wField' referenced in bootstrap

What I have:

Drop. Melee Weapon Attack: +3 to hit, reach 0 ft., one creature.
Hit: 3 (1d6) piercing damage per 10 feet fallen, up to 21 (6d6) damage. Miss: The piercer takes half the normal falling damage for the distance fallen.

What is should be:

Drop. Melee Weapon Attack: +3 to hit, one creature directly underneath the piercer.
Hit: 3 (1d6) piercing damage per 10 feet fallen, up to 21 (6d6) damage. Miss: The piercer takes half the normal falling damage for the distance fallen.