Empty Trash may not delete folders in the Trash if using network home directory
Users who have home directories that mount using AFP server may find that folders remain in the Trash after emptying the Trash, either from the Dock icon or from the Finder menu.
Loose files that are not contained within a folder will be deleted as expected, but folders and their contents may remain. The Dock's trash icon will still show that the Trash has contents, even though the Finder's visual progress indicator suggests that the Trash has been emptied without issue
Mobile home directories are not affected by this issue.
Update to OS X Lion v10.7.4 or later.