If you are in the old bridge district (exactly the right bottom side)and try to use the walk option in the map menu to get to a house at the other side of the wall,nothing happens. But at the top side of the district is a gap in the wall,so normally you should be able to reach the buildings with this method.
There is a limit to how long a path can be before the 'find me a way to get there' algorithm gives up. This is the problem you are running into. You can find the same thing happen if you are in Old Kenmore at, for instance, the Old Theatre and you want to get to SlayerNZ shipping.
The work-around is to go to the S-Mart (which is short enough to be found) and then to wherever you wanted to really get to.
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