Help! Norton won't let me download Acrobat Pro DC!

I've just gotten the Redemption Code for Acrobat Pro DC, followed the links to enter the code and downloaded the installer - but Norton doesn't want me to install it because it's too new (less than 5 people have downloaded it) and its recommended action is to delete the download altogether. Is this a new patch, or something else going on? And what do I do to fix it?? (Note: very non-technical, so plain step-by-step instructions much appreciated...)