[ubuntu] blank screen boot from cd Macbook Pro 13 inch Mid 2012

there's a blinking cursor whenever I insert the ubuntu 12.04 cd in. I've also tried the ubuntu 12.04 precise pangolin amd64 for mac. it showed the same thing.

I have made 50gb of free space for it using Mac's disk utility.

I've read I had to set nomodeset noapic or something but I can't access that menu. it's just the blinking cursor.

any clues on how to fix this?