When I do an advanced search in Outlook 2000, I get the message: "There are too many Find Public Folders Dialogs open. You must close them in order to use the Advanced Find. Do you want to close them now?" I respond yes. Then it says: "Outlook cannot perform your search. Outlook cannot display this view. The folder already exists." Any ideas?
The problem, according to Microsoft Knowledge Base article Q240697, is that a previously-defined Advanced Find was saved and is now corrupt. Fortunately, that article includes a solution to this problem, as well. You'll need to log off of Outlook, then go to Start | Run and enter the following command: outlook /cleanfinders.
This will remove your saved searches and fix the problem.