I am new with xampp, i am using ubuntu aswell x86 same version, i am a noob in ubuntu also i had some problems whith mysql not starting all were permission issues becouse i was tired of using sudo and gedit to edit stuff and save them, so i changed permission to the regular user and that changed my lampp folder to my regular user, and when trying to get xampp to work it coulnt start mysql at all, so unistalled xampp and reinstalled again.. that fixed the problem..
try reinstalling, redownload the xampp tar again and see if that make any difference...
I downloaded xampp to my desktop and used this command :
sudo tar xvfz /home/your-user/Desktop/xampp-linux-1.7.1.tar.gz -C /opt
since the info at xampp website its was a little confusion for someone new like me..