Autocad - Bpoly not working as expected

I don't have a current AutoCAD available to open your file.  But, I would suggest that you verify that none of the lines cross over each other which might make it an illegal boundry.

Kind of strange - it looks like 56 is highlighted indicating it was found.  Does the input near 52 have to identify a line like between 61 and 62?  Also, the long line at the bottom of the squares in question looks like it could be a different polyline.  I was able to find a viewer to look at it but I couldn't manipulate it.

That sounds reasonable.  I do remember doing that in the past.  When, joining lines into polylines I think the ends must match closely or the program adds in small lines to join.  I know it is difficult to get the endpoints to match up.  I remember using snap to endpoint to make sure they form a closed area.

I don't know if I helped all the much.  Do you have any more questions about this?

Sounds okay to me.  Save the points for the next question.

Since what I have done is working, I guess it is appropriate to close this as such. Thanks for your input.