The Ubuntu installation does not create swap partition. This issue happen with both 12.04.2 and 13.04.
I tested it with two diferents pc and with a virtual machine in virtual box into Ubuntu. I tried both automatic and manual installation options during installation.
The partition is created but with errors and the system can not mount the partition swap at startup.
I solved the problem by booting the system from pendrive, then start gparted and format the partition again. This worked for only a few days.