A matter of quickly replacing the hacked DigiNotar certificates, avoiding any negative effects as a result of decisions by web browser makers and other online businesses to stop trusting those compromised certificates.
Dutch language news articles:
http://www.nu.nl/internet/2611981/black-out-overheidssystemen-afgewend-hack-diginotar-.html
and
http://www.nrc.nl/nieuws/2011/09/10/onderzoek-nrc-platgaan-computers-rijk-net-afgewend/