my sopc builder can't generate

system is not editable

checking component catalog at www.altera.com for updates...

problem with catalog at http://www.altera.com/pwd/megwiz/getupdate/root.xml: (http://www.altera.com/pwd/megwiz/getupdate/root.xml:)

problem checking for web-updates(unable to download component catalog,try again later)

above are the error.The sopc builder can't generate.Please tell me why?