А если использовать 
import win32com.client
т.е. так:
- import win32com.client 
- import array 
-   
- app = win32com.client.Dispatch("AutoCAD.Application") 
- acadDoc = app.ActiveDocument 
-   
- files = r"сектор-план" 
- insertionPnt = array.array('d', [377.7541,304.5495,0]) 
- acadDoc.ModelSpace.InsertBlock(insertionPnt, files, 1, 1, 1, 0) 
получаю ошибку:
    acadDoc.ModelSpace.InsertBlock(insertionPnt, files, 1, 1, 1, 0)
  File "<COMObject <unknown>>", line 5, in InsertBlock
pywintypes.com_error: (-2147352567, 'Ошибка.', (0, None, None, None, 0, -2147024809), None)