I have checked your uploaded files.
ElecSchema_SLD.dwg contains only one AutoCAD point object at 0,0,0 on the "Config" layer.
The DuctEdge.shp https://en.wikipedia.org/wiki/Shapefile
contains 1795 (rectangular) polygons with a table containing various object data.

With MAPIMPORT you can get polylines with attached object data in AutoCAD MAP/Civil 3D.
>> I am trying to import a shapefile with a table attribute to a cad file that already has almost the same table.
Your uploaded DWG does not contain any Block definitions with attributes nor any Object data tables.
Your screenshot shows a customized Blockattribute editor, but you cannot import shape object data as block attributes
directly, if you don't have a point shape but a polygon shape.
Upload a sample CAD file (with blocks with Attributes) that shows correct information when using your custom command EDA. Maybe ist possible to convert the shape information to blocks with attributes using some lisp programming.
What is your intention, what do you finally need?
Gruß Udo Hübner (CAD-Huebner)