this item mysteriously dissapeared from my inventory, does anybody know why?

Uhm, did you hang it around one of your characters' necks? Drop it on the ground somewhere? Sell it? Let your younger brother play IWD with your save file?

It shouldn't 'just' disappear, either you did something to it or there's a nasty bug at work. Load an older save and try from there would be about the best advice I can give you. That, and maybe d/l a patch

My game is patched and im the only one that plays it. I was reading a walkthrough online and it says that you need the wolf's charm for the lever? But it doesn't elaborate.

You need it in your possession, but I'm not sure whether it needs to be equipped (worn) necessarily. As long as you have it, you can pull the lever and carry on into the next area.

It's been a little ways back so I don't fully recall if anybody gives you anything in the Vale(I don't think so) but maybe you got hit with the inventory item dropped situation? Just a thought.

<font color = mediumspringgreen>Ozzman,

If that happened to me, I would not feel guilty about hacking it back into inventory using Dale Keeper.</font>