I changed the button layout to w = forward, s = backward...and so on. But the problem is that in game the w and s makes me walk diagonal in that direction.
Ex. When I push w it makes me walk forward + left, s makes me walk backwards + right
Is there a solution?
Playing on Win 7 64 bit

Make sure that none of your other keys are in conflict. I noticed when I remappd my keys for Blood that a lot of my walk keys were in conflict with other commands.

I think I figured it out! If you drink to much in the game your character gets drunk and have problem walking. Brilliant!
Read about it in the manual but did not think it would effect the game.

Yea that will do it alright, watch out getting too drunk as you literally can't do anything and it takes quite a while for the effects to wear off. Eating food will lower the drunk level and restore hp so you need to balance eating food and drinking to keep control of your character.
Generally drink first until nearly drunk and then eat something to bring the level down(only as much as you need to restore your hp though).