Apparently, some of the new display methods in Nero 7.7.5.1 caused a brief virus scare. Nero has posted a message on their website, stating that there is no threat and that the warnings should not appear once you update your virus definitions.
With development of Nero 7, we used innovative methods to display pictures and videos. Some of these methods were used for the first time in version 7.7.5.1 and adapted to Windows Vista. As these methods were previously unknown to antivirus software manufacturers, this resulted in a virus warning being displayed during the installation of Nero 7.7.5.1.

Please be advised, these methods have been examined by antivirus software manufacturers and have been classified as harmless. The relevant updates of the virus definitions have been carried out. Once the antivirus software has been updated, virus warnings should no longer appear during the installation of Nero 7.7.5.1.
Now if Nero would just make it easier to disable Scout. More information can be found on Nero's website.