I worked on multiple ArcObjects Desktop applications several years ago. In those project, I needed to add some references, e.g. ESRI.ArcGIS.ADF, ESRI.ArcGIS.Utility (this one is in ESRI.ArcGIS.ADF?), etc., which could not found in my CPU. Where could I find their dlls? Besides, in the created project, I could not add ESRI.ArcGIS.Geoprocessor.dll and ESRI.ArcGIS.GeoprocessingLib.dll. The error message shows that the xxx.dll can't be added. Please make sure that the file is accessible, and that it is a valid assembly or COM component. Please help if you can. Thanks.
The ESRI.ArcGIS.ADF assembly was replaced at 10.0 by several assemblies. See the help documentation under the heading of New Assemblies. For example, if you're using comReleaser, you'll have to load the ESRI.ArcGIS.ADF.Connection.Local assembly. The assemblies ESRI.ArcGIS.Geoprocessor and ESRI.ArcGIS.GeoprocessorUI (I couldn't see a ESRI.ArcGIS.GeoprocessorLib assembly) have to be loaded using Add Reference instead Add ArcGIS Reference. This is also true for any of the toolboxes (DataManagementTools, etc.).
I use VS 2010 to Add Reference, and got the error for Geoprocessor and GeoprocessingLib, but OK for many other dlls. Searched my C:\ and could not find ESRI.ArcGIS.ADF assembly and GeoroprocessorUI.dll.