I saw this win watching a vid some times they build them self's in to a wall don't know if it a bug but thought it might be
Version Found - 0.0.250
Construction workers are not intelligent in their choice of order when building things such as walls. Inevitably, this leads to workers building themselves in, like so:
(sorry for the big images; spoiler tags didn't seem to work for me :/ )
(http://i.imgur.com/xxFavPL.jpg)
(http://i.imgur.com/WWiLrcd.jpg)
Unfortunately, when this happens, one must sell the just-created walls, losing money.
Sometimes this is so bad that it is necessary to babysit the workers, adding one wall tile at a time to ensure that they do not get stuck.
Obviously, it would be preferable if they looked at the wall and chose to build from the inside-out to avoid getting stuck.
As a side-note, you might want to try to leave some space for repairing between your walls and apparatuses/mountains/whatever.
The wall Coleman is stuck in, for instance, can't be reached by colonists (well, once Coleman is not there anymore, of course), and thus will suffer from degradations (wear and tear) and ultimately get destroyed.
The colonists are either too stupid to not build their way out, or the pathing system just needs some enhancements that will come with time.
Will report in bug tracker.