Whenever I try to install a mod the mod doesnt work. I have modloader, modloaderMP, forge all installed. and i already have deleted meta-inf. My minecraft doesnt crash or get a black screen or anything like that, the mods just dont work for some reason. and for the piston mod i can get the double piston by going to creative mode and getting one but i cant craft one. and i cant craft a backpack either using the backpack mod. but the verical redstone mod works. I just copy and paste the zipped mod into the mod folder. could someone please help me?