If you don't have a reference checked in the tools > reference > AutoCad xxxx type library it will have errors, the getobject function will not work. I am sorry I forgot to tell you that.
Public Graphics As AcadApplication
Public Sub OpnAcad()
Dim AngBracDwg As String
On Error Resume Next 'I added this line
Set Graphics = GetObject(, "AutoCAD.Application")
If Err.Description > vbNullString Then
Err.Clear
Set Graphics = CreateObject("AutoCAD.Application")
End If
AngBracDwg = "c:\dwg\ba1.dwg"
Graphics.Documents.Open (AngBracDwg)
On Error goto 0
End Sub