Sounds like it has something to do with the software subscription. I don't think that you're suppose to "log on" to nero though. Anyway, I wouldn't know. I'm using the w4r3z version .
Then I guess that should be problem. He probably used it while online. Since some programs check if the registration info is legit if they detect an internet connection. Thats why I always turn off my internet when using w4r3zed programs >_<.
Try either re-installing if you still have the setup/registration info/crack or find a new registration key/crack.