After asking many people, I just had the solution.

Some equipment disable magic use.

If the same thing append to you try to desequip all.

Hi ! I've got problems to use magic. I already drunk the mana potion and touched the mana seed. So, I have the magic Skill : http://img4.imageshack.us/img4/8923/compvq.png I also spent few points to have enough magic points : http://img19.imageshack.us/img19/2348/comp2g.png The problem is... it just...