Scheduled Maintenance: We are aware of an issue with Google, AOL, and Yahoo services as email providers which are blocking new registrations. We are trying to fix the issue and we have several internal and external support tickets in process to resolve the issue. Please see: viewtopic.php?t=158230
Debian may not be for you. Installing Ubuntu won't take more than 20-30 mins depending on your hardware. Ubuntu also does not need hunting for random lib packages to install Viber. While I'm at it, use Software Center, don't unzip .deb file.
As with any install, backup all data on an separate drive.