Just kill all the cats (except the kitty and Arhu).

Did you talk to lieutenant Robin, in the north west corner of Ars Magicana?

That quest in particular is relatively easy to partially mess up. <img src="/ubbthreads/images/graemlins/disagree.gif" alt="" />

Some others have run into problems with the hot keys, but fix it by re-assigning them.
See also; Tutorial-Changing F1-F12 hotkeys to different keys

Agility effects if you get hit; armour helps determine how much damage you take when you do get hit. Higher armour is better, but within reason, I would take better bonuses over higher armour.

Get an ergonomic chair. <img src="/ubbthreads/images/graemlins/biggrin.gif" alt="" />