Exchange 2K Public Folder access

My users can not add folders to other Public Folders in Exchange 2000. They can create folders at the top level but not on subfolders they did not create. From Outlook, right clicking on the folders and going to Properties and then permissions the Default name is set to Author. When they right click the Add Folder option is grayed out. I checked perms in Exch2K Sys Manager. Everyone has the right to Create Public Folders, Create Top Level Public Folders and Create named prop… At one point they used to be able to do this and I’m not sure when it stopped. Thanks.