If the patents for ur earlier version for nero has expired, it will ask u to upgrade to nero 7 ( latest is nero version 8)..
If u dont do that certain appln will not work like NERO VISION ESSENTIALS OR NERO RECODE ESSENTAILS etc... but appln like nero express and nero burning ROM will work in all cases.
But if the patents have not xpired then i think it is just asking u to upgrade as there is a latest version is available on the net ... the it would be ur choice to upgrade or not ....
IF u upgrade , it will cost u as upgrade is not free ,....
U will have to provide ur credit card deatils
for further details