I checked the .dwg file and when regenerated, the linework intersects in those locations, however, there are gaps when the circles/arcs are simplified graphically, even when using autocad. So, there is an issue importing these elements
I did try Didier's projections and Thom Thom's edge tools and still having a heck of a time getting faces formed. Even drawing new lines/edges is not helping.
Are there any tricks in prepping the .dwg prior to import that will help?