Cannot delete files with long filenames

I tried to delete the "users" folder from a backup copy of my C drive. The backup is on another disk. I get the following message: "the source files are larger than supported by the file system...." The files are buried deep in the users folder. I am not able to rename them. I don't know how to delete them. Any help appreciated.
See attached imageshack image.

http://imageshack.com/a/img661/2151/KVM965.jpg