I develop .Net Com Class Library on 32-bit Windows XP and when port it to 64-bit Windows-Server 2008 client code
var t = Type.GetTypeFromProgID("ProgID");
var a = Activator.CreateInstance(t);
failed with error mentioned in my question subject There was similar discussion Retrieving the COM class factory for component with CLSID {XXXX} failed due to the following error: 80040154
I double checked the platform target
(Project Properties / Build / Platform Target) I build my com .net assembly for -- it's x86
But the problem still present on 64-bit Win2008 Server...
What shall I check?