Thank you for responding. After working at it a bit yesterday, I finally figured it out.
You have to highlight all walls you wish to dimension, including the exterior walls. After doing that, start at one point along the wall you wish to dimension,then pull your cursor all the way to the other end of that wall. But wait, there's more. Move your cursor perpendicular along the inside of the wall ( it doesn't seem to mater how far ) then move back to the first exterior wall, then down to the original starting point. In other words, Draw a box.
I am attaching a jpeg with a red polyline drawn for emphasis. I started ( and ended) in the lower left corner. I hope this may help some one in the future.