Fixed
The bug has been fixed. See the Version Fixed and Additional Information, if applicable, for more information.
Workaround
You can't pass in an ATL smart type for the data to overwrite, but must declare it as a simple pointer to IUnknownTo make the sample code work, change the var type of pToOverwriteMap from IUnknownPtr to IUnknown***** Please document this usage in the documentation ****A good place to document the proper usage of the IUnknown* parameter (as opposed to the IUnknownPtr type) would be either:(a) Since this likely affects other utility methods, esriSystem library overview; or(b) The discussion on ATL smart types, found here:<a href="http://edndoc.esri.com/arcobjects/9.1/default.asp?URL=/arcobjects/9.1/ArcGISDevHelp/DevelopmentEnvs/COM/VCpp/SmartTypes.htm" target="_blank">http://edndoc.esri.com/arcobjects/9.1/default.asp?URL=/arcobjects/9.1/ArcGISDevHelp/DevelopmentEnvs/COM/VCpp/SmartTypes.htm</a>