Quest help in runescape, PLZ HELP!?

in tai bwo wanna trio i need to use Karambwan paste with a spear, but it won't do it! I did not catch or cook the Karambwan myself because i don't have the right lvls, i already used a cooked karabwan in a pestal and mortar, and now i try and use the paste with the spear and it will not work, so can anyone help????