That's pretty much the problem. I was trying to restrict some heraldic items to a certain faction and this is what happened:
This is my code:
["mod_tab_shield_kite_c", "Kite Shield", [("le_heraldic_norman_kite_shield_4" ,0)], itp_type_shield|itp_wooden_parry, itcf_carry_kite_shield,
150 ...