So I searched PAE in /boot/config and I don't found it... However, I searched in incorrect config file... I searched in 2.6.32-5-686. Sorry... But I am running linux-image-2.6.32-5-xen-686 now and the free command shows 3 GB only. What is the problem?
# uname -a Linux base02-rede 2.6.32-5-xen-686 #1 SMP Sat Jul 24 07:00:17 UTC 2010 i686 GNU/Linux