I got the Ubuntu 11.10 32-bit edition and i used Unetbootin to write the ISO to a usb stick.After that i tried to boot from the stick,having changed the BIOS boot settings,and when the first interface shows up with the choices of istallation,whatever choice i select i got the message"invalid or corrupt kernel image".I use a netbook with windows 7 on it.I tried different usb sticks but same again.I also tried Universal USB installer instead of Unetbootin but same again.Any idea of what happens?I am using ASUS 1000H.The USB doesn't work in one more PC i tried to,but i also tried a second USB to both of the two computers and same again. I downloaded the ISO image once again and follow the same procedure but same again
You can verify downloaded Ubuntu images using
Now you can compare that against the Ubuntu Hashes page. In this case they match up meaning what I downloaded matches the original copy (with 99.99something percent accuracy).
If you downloaded an ISO not on that list you can usually still find a hash but it depends on the ISO's source. If you grabbed it from the daily page, there is a MD5SUMS file in there but it obviously changes every day.
If you can't verify the image, download it again and check it right away. It might be worth using the Bittorrent download options as that has built-in checking.
The following doesn't apply to you (you've already swapped out USB sticks, strongly suggesting it's an image issue), but it might help people in the future.
If your image verifies correctly but still doesn't work, just try copying it to the USB stick again. In some cases you might find you have a stick that just refuses to work (I've had a couple of old, cheap disks not boot Ubuntu. I later found out that they were just shredding any data going in and out of them so chucked them. In other words: you might want to try another stick.
I've had the same error previously, I solved it by formatting my USB to Fat16 format and then using the Universal Windows Installer. Give it a try.