Pretty sure you need at least level 1 in the Traps skill before you can make any traps. You may have to try disarming traps until you level to 1, find the traps skill book, or start with points in that skill.
Speaking of which, Iād really like to make it possible to train up any skill provided you have the right tools to start it, rather than having a few (archery, traps, formerly electronics) where your options are āstart with it, grind on something really annoying, or get lucky with book dropsā.