hi im dimstar_DM
i made a gta iv knife bloody its a simple thing

to install
first extract the w_knife.wtd on a place where you can find id fast then
use open iv or spark iv then when started one of thes programs search for the file weapon.img
findable in gta iv direcotry\pc\models\weapons.img

afther you opened weapons.img find the file w_knife.wtd then when you selected the file (for open iv) select replace and find the extracted file from the rar (for spark if) select imput button and find the extracted file from the rar

then save it and you have the mod
enjoy