*The wall already has gates in other areas
*I am allowed to build 2 wall segments to "close it up" but just not allowed to gate it
*The paving stone cannot be destroyed which was what I thought was the original culprit.
50 Silver in boston to the first person who can figure it out

http://tinypic.com/r/2ibkb68/6
http://tinypic.com/r/312imj4/6