Create a new database.
Add an Asset Publisher to your page.
Click on Add New -> Basic document.
Fill the Title, and browse a file.
On 6.2.x: When you Publish, there will be an error message: "Please enter a unique document name.", but there are no any info in the error log.
On M4: After you Published, the dialog box closed, and an error message appears on the Recent Content page: "You do not have the roles required to access this portlet."
If you go to Control Panel -> Recent Content, you get an NoSuchResourceActionException in the log. See the attached file.