I've tried for many hours to install the debian-edu-7.1 on a school server which worked flawless in February this year. It failed yesterday.
After comprehensive testing of all the availiable install options, I got a summary with screenshots showing where the installation of the CD-version of the ~700 MB ISO stopped (debian-edu-7.1+edu0-CD.iso) . Please look at the keyring-issue error messages from the screendump on *02.png and *03.png:
The errors are reproducible in VirtualBox, also trying the debian-edu-amd64-i386-NETINST-1.iso.
Not being successful using the CD-version of debian-edu-7.1, I tried to "burn" the +5 GB USB-version of the ISO-image on a USB-stick. This by using usb-creator on kubuntu. This failed. The error message: http://d.skolelinux.no/~knuty/sl-test/debian-edu-cd-feiler-06.png