I tried to install Ubuntu 12.04 Server (64bit) on a Dell Insprion n5520 using a USB stick. I used the Universal-USB-Installer-18.104.22.168 which has support for 12.04 server but you can also replicate the problem with LinuxLive USB Creator 2.8.11 or unetbootin 575.
The computer boots up the installation process ok. It gets through the Ubuntu language, locale and keyboard selection. Then starts loading additional components. At this point it gets about a quarter of the way through then throws big error message saying "There was a problem reading data from the CD-ROM."
When I Press no
this error arise
Installation step failed. An installation step failed. You can try to run the following item again from the menu, or skip it and choose something else.
The failing step is: Load installer components from CD
What should i do ?