Go to your profile
In the left column
you will see:
Ignore Boards Options - you can check off the boards you want to ignore - click change profile at the bottom when you are finished.
Buddies/Ignore List - click on the tab "Edit ignore list"
Go to "Add To Ignore List" at the bottom Type in the person's USERNAME that you want to ignore.
You can remove people from your ignore list by clicking the red X on the right in their row.
Please post a reply to this thread if this isn't working.