11.04 - Checksums do not match when creating a bootable USB stick

Since karmic koala, I can't create a bootable USB. Always the same error, it arrives to 96% and then this error " checksums do not match". Also in lucid, meerkat and natty even with fresh install. Tried it with more than USB stick.

Am I doing somthing wrong? I did format the USB stick several times but no luck. It's 2Gb.

Now I lost my DVD drive on my laptop, and USB is my only option. Please help!

1. I did try different USB sticks


2. I did try unetbootin, with success, but when booting from USB and selecting check disk for errors within the unetbootin menu it gives me 1 error, so I didn't try actually to install the O. S for precaution reasons.



3. I did try to launch disk creator from terminal with sudo and that gives the same error on 96% of the process.




4. doing the check proposed by chen xiao-long, the codes result no match.

   
   
   

   suliman@suliman-laptop:~$ sudo mount -o loop /home/suliman/Documents/ubuntu-11.04-desktop-i386.iso /mnt
   [sudo] password for suliman: 
   
   suliman@suliman-laptop:~$ md5sum /mnt/casper/filesystem.squashfs
   174bb50daab963e681d2dcd9603f737b  /mnt/casper/filesystem.squashfs
   suliman@suliman-laptop:~$ md5sum '/media/8BE1-C58A/casper/filesystem.squashfs' 
   e4129f8ff21860d978c911b3b394f807  /media/8BE1-C58A/casper/filesystem.squashfs
   




5. if the usb port is faulty, how can i check that?

problem solved, but no answer to the question. i used unetbootin with success but the problem with ubuntu disk creator remains.