Outlook2000 and Archiving

My incoming mail server is IMAP, I archived partially my mail couple of days ago. Now I’m trying to retrive saved PST files using: File, Open, Personal Folders File and the only folder I oppened is Personal Folder with Calendar, Deleted Items, Journal and Task. I lost Inbox and Sent Items folders. I’m sure there is a way to get my lost folders because size of archive.pst is 6MB