Thanks . Do you get that error message in all Outlook folders (Inbox, Sent Items, Deleted Items) etc...? If you send a new e-mail to yourself, does that appear as expected?
Also, if you go to File > Account Settings and then click on the data file tab. From here you should see the path where your e-mails are stored. If you can navigate to this folder and see how big the data file is, that may indicate if there is any data there.