problem with inventory.lua while auto repair

[hpkid2002]

when i tried using merchant npc in Ystra Labyrinth, after buy pot, i got this error. still no clue but i think i got something error with

if self:getItemCount(bestItem) < quantity then
numberToBuy = quantity - self:itemTotalCount(bestItem);
printf(language[1001]); -- Shopping
for i = 1, numberToBuy, 1 do
RoMScript("StoreBuyItem("..bestItemSlot..")");
printf(".");
end
printf("\n");
end

return true;

[Administrator]

Using outdated scripts will do that.