I've placed a note in the world, http://i50.tinypic.com/34j9f9g.png and when the player tries to take the note, it's not possible. The only way to grab it is to 'tcl' through the wall and grab it from behind. The only thing I've tried is rotating it 180 degrees. Any help appreciated.

It's probably enveloped by the wall's havok data. Try moving it away from the wall slightly. If I remember correctly, you can toggle the rendering of havok wireframes via the f4 key.

Cipscis

Most likely the note's geometry is inside the geometry of the wall its placed on. Try putting a small table there and putting the note on the table, or moving the note to a place where its outside of the surrounding geometry. Pressing F4 in the render window of the geck will toggle the collision geometry, so you can see if the collision of the note is behind some other object's collision.

Edit - Ninja'd while trying to lookup the collision toggle button (I forgot what it was)...

Yep, that worked. Thanks guys