All folders on Postfix mail server are subfolders of Inbox. The folder name must start with Inbox. For example, if you want to create a folder Test, you need to enter the name as Inbox.Test. The folder will be created as a subfolder of Inbox. It is impossible to create folders on the same level as Inbox.
If the Inbox. part of the folder name is omitted the mail client will give an error message without explaining why the folder cannot be created.
This information pertains to both DeskPilot and conventional e-mail clients like Outlook Express or Eudora.