fail to install new software in nsight

hi,

i have a problem that i install new software in nsight by using http://download.eclipse.org/releases/juno/, shows "Unable to read repository at http://download.eclipse.org/releases/juno/.
Unable to read repository at http://download.eclipse.org/releases/juno/.
No repository found at http://download.eclipse.org/releases/juno/201303010900."

thanks
hanbin