Sam, reading the coordinates in the netsize function is very strange. I have un-commented line 124 (and 125) but the ENgetcoord function still returns zeros - does it work for you? I have looked at the addcoord function which is called from line 124 and I'm not sure the coordinates are saved.
From my point of view, the DLL should enable the user to load, and use, all the data from the INP file. Maybe a separate function just to load the coordinates before they can be accessed.