Item upgrade adding attributes. TFS 1.4.2/otclient redemption

[eardrums]

Hey guys,
I'm trying to a very simple script to upgrade a weapon. Still just trying to learn how it all works and I cant figure out a specific section.

here is the script

function onUse(player, item, fromPosition, target, toPosition, isHotkey)
    if item.itemid == 2385 and
    player:getItemCount(2147) >= 10 then
    
    item:setAttribute("attackspeed", item:getAttribute("attackspeed") + 5)
    player:removeItem(2147,10)
    player:say("WOOT!", TALKTYPE_MONSTER_SAY)
    
    elseif player:getItemCount(2147) < 10 then
    
    player:say("You do not have enough upgrade materials.", TALKTYPE_MONSTER_SAY)
    
        end
    return true
end

In the item:setAttribute part. Putting in attack,defense, or attackspeed all work. but when i try to add sword fighting or anything else for that matter it doesnt change the sword and if i try to upgrade a 2nd time on top of that it crashes the server. instead of "attackspeed" i put in skillsword for example. What am I doing wrong?
thanks!