Norton AntiVirus 2011 is apparently so effective at killing malware that it hasn't seen enough of Norton Power Eraser and the Norton Bootable Recovery Tool to recognize either one (he says with tongue in cheek.)
This is just a notice to whomever looks after these things that upon downloading Norton Power Eraser and the Norton Bootable Recovery Tool, NAV 2011 says: "Number of users in the Norton Community that have used this file: Unknown." and "This file release is currently not known."
Obviously, these are good files. I just thought that NAV would automatically recognize a file from Symantec. 