Have you tried using the mini.iso to install? This will pull the latest packages from the internet instead of the install media. This is how I do the majority of my installs.
I tried to input the links, but they were getting truncated. Search for ubuntu precise mini.iso and your architecture (32-bit or 64-bit)
You will need to download the mini.iso for your architecture and "burn" the .iso image to your USB stick.