@jawad I use Centos7 so am not an Ubuntu expert.
But,
If the install completes I wouldn’t worry about that error as you are using Ubuntu 14.04 (Trusty Tahr) not Ubuntu 15.10 (Wily Werewolf) . So no problem.
Make sure you sudo apt-get update # Fetches the list of available Ubuntu updates sudo apt-get upgrade # Upgrades the current Ubuntu packages sudo reboot After major Kernel changes
Hope this helps.