You might be able to empty the trash via the Files menu of
OnyX OnyX uses "sudo rm" as does Cocktail, TinkerTool System, MacPilot, and probably half hundred other utilities. There is no extra effectiveness because it is in an app other than being less subject to typographical errors on the part of the user.
If file is hung, whether it is in the trash or elsewhere, booting from another volume as Artie suggested,
may release whatever has the file locked and allow it to be deleted.
But if that does not work, I would try boot from the Recovery Drive or any other available bootable volume and run Disk Utility > First Aid, Drive Genius, TechTool Pro, or other volume repair utility.
