Please Help: Installation Failure Options

[yabbadabba]

I am having great difficulty installing Ubuntu on my Macbook Pro 8,1 alongside OS X. I had this system dual-booting, but I used the Live CD to install, but I formatted because I want an encrypted install.

With a USB disk I have attempted installing every version of Ubuntu with an alternate .ISO available. Most fail to install a Kernel, however, 12.04 installs a Kernel, and the rest of whatever constitutes the base system, but crashes somewhere after 90% in the "Select and Install Software" section.

GRUB still installs fine, and boot to a Shell on the Crypto Partition, but when I try "sudo apt-get install ubuntu-desktop" it asks me for the CD for the distro I am attempting to install. I was under the impression apt-get installed via the internet.

I just want to have Linux back on this box. I must dual-boot, because I need proprietary software for work, but I want to encrypt my personal OS. Please tell me what you would try or if this is a known issue, how it was resolved.

Thank you very munch.