How do you delete a file that is "locked" or otherwise undeletable?
There are several free program options that you can try to when receiving messages like the one above, "You need permission to perform this action."
The best known is Unlocker, and you can download it from their website: http://www.emptyloop.com/unlocker/
Another option is FilExile, and you can read about it at makeuseof.com: http://www.makeuseof.com/dir/filexile-simple-tool-delete-locked-files/
Or you can go directly to sourceforge.net to download the file.
Ghacks.net has a good article on FilExile: http://www.ghacks.net/2012/02/22/filexile-lets-you-delete-files-that-refuse-to-be-removed/
Best of luck, and if you find any other useful tools to remove locked or undeleteable files, please include a comment.