After doing these add_structs I still have a showdescription error in inventory and equipment. Not sure where to place those or what to use as the void* data that the add_struct calls for. Here is what I have done so far and not sure if these are even correct.

add_struct(NHAC_CINVENT_CELLS[NHAC_CINVCELLS], sizeof(RPGItem));
add_struct(NHAC_CINVENT_EQUIP[NHAC_CINVCELLS], sizeof(RPGItem));
add_struct(NHAC_MOUSEITEM, sizeof(RPGItem));