Never thought of low attitude, cause I've always got a high one very quickly <img src="/ubbthreads/images/graemlins/shame.gif" alt="" /> - and I didn't rob Walker at the beginning, only when I had the lockpick lvls I needed for the chest (lvl 4). So I had quite some time to buy many potions from him.
Try this: Sell stuff to him and let him get more than it's worth. If his attitude is above 50, try stealing again.
Kiya
