Administrator no permission to change permissions !

I saw "McAfeeSafariHost" in the login items window of my system settings. Not knowing what it was and having been receiving annoying popups about McAfee, I click on the i icon next to it. This brings up the Launch Agents folder where I find the file "com.mcafee.McAfeeSafariHost.plist". When I try to view this file with TextEdit I get a message saying that I don't have permission to view this file and I should go to the GetInfo window. In GetInfo it shows system with read&write access and everyone with no access. When I try to change the everyone permissions I get a popup with "the operation can't be completed because you don't have the necessary permission"

I am the administrator and sole user of this device. How is it that I am unable to get permission to either view this file or change the permission settings?