To give yourself rights to the report server you need to login to the report manager
"http://servername/reports" or whatever it has been setup to use. if you can't reach that site ensure reporting services has been installed correctly by logging into the server and checking the reporting service configuration. if you can connect to the report manager in your browser click on security and add your AD account and give full permissions. if you don't get an administrator to login to the website and give you rights.
Also ensure your trying to upload to the reportserver and not report manager.
reportserver = http://servername/reportserver
the below article may be of use.