It's probably because it's an early 2013 issue or even 2012 one. The current software is totally compatible with Windows 8/8.1.
During the installation were you offered an alternative of creating an online account and downloading from there? If you were and refused that I suggest re-running the installation and choosing that option.
It's possible also that it may be reacting to an existing antivirus product or traces thereof. Did you have one installed?
If all else fails I would contact Technical Support, it's free of charge by phone or online chat and linked under Useful Links at the top of this page.