This article is extremely useful when trying to get the EnumerateResourcesActivity to work in the FIM workflows: http://c–shark.blogspot.com/2009/04/how-to-use-enumerateresourcesactivity.html
I don’t use the activity too often and forget that the designer code behind needs to be modified to add a code activity (which isn’t add via the UI) to the EnumerateResourcesActivity.