child categories and pretty permalinks

I’ve got my permalinks set to: /%category%/%postname%/

So, if i have a post called “joe” in my “personal” category, it shows up perfectly as:

http://www.myblog.com/personal/joe/

However, if I create a child category of “personal” called “friends” and categorize my “joe” post as “personal > friends”, then my URL comes out like this:

http://www.myblog.com/category/personal/friends/joe/

Why is that extra “/category/” showing up? and how can I get rid of it. the comments here seem to be talking about this problem, but i couldn’t get the solutions to work.

any help would be most appreciated