Usb boot fails

Hi,

I have prepared a usb stick with gparted 0.5.2-1, following choice 1 here http://gparted.sourceforge.net/liveusb.php . The so prepared gparted usb stick boots and works perfectly on my laptop, but it fails somehow on my desktop: it is recognised by the bios, the boot possibilities (normal, failsafe etc) are shown, but whatever I choose, I am sent back to the same menu. I don't know how to solve this, also considering that the Ubuntu usb stick boots and works perfectly on the same desktop.
Any suggestion?

Thanks