You access an IBuildCatalogs interface object by calling the IBuildServer.BuildCatalogs property, as in the following example, where objBuildCatalogs is the name you give to the IBuildCatalogs interface object:
Option Explicit
On Error Resume Next
Dim objSearchAdmin, objBuildServer, objBuildCatalogs, objBuildCatalog
Set objSearchAdmin = CreateObject("Search.SearchAdmin.1")
Set objBuildServer = objSearchAdmin.BuildServer
Set objBuildCatalogs = objBuildServer.BuildCatalogs
objBuildCatalogs.Add "KMSampleCatalog3", "C:\Catalogs"
Wscript.Echo "The following catalog definitions exist on this host:"
For Each objBuildCatalog in objBuildCatalogs
Wscript.Echo " " & objBuildCatalog.Name
Next
'Release objects
Set objBuildCatalog = Nothing
Set objBuildCatalogs = Nothing
Set objBuildServer = Nothing
Set objSearchAdmin = Nothing