ERROR: User does not have required permissions. Verify that sufficient permissions have been granted and Windows User Account Control (UAC) restrictions have been addressed.
This happens when you are on the server and want to administer report content from the server. In short, the problem is that the local user does not have permissions. It appears to be a bug in the how permissions get set up within SSRS.
Run IE, Firefox or whatever as administrator
Navigate to http://localhost/Reports - (Do not use http://<server name>/Reports)
From the Root Folder, Click on "Folder Settings" as below
Click on New "Role Assignment" and add "Content Manager" to the person you want to administer your content