Thanks you can do one of two things. The easiest is to press and hold the apple command key, while you select empty the trash.
The other is to select the item in the trash and then go a apple command i. In the middle of the window that come up you will see both stationary pad and locked. The locked box should be checked. Selected the locked check box, to remove the check mark.
Once this is done for each of the files, that are causing the problem. You should be able to empty the trash.