Trouble on Macbook 3,1

So. Just getting started with Linux, and I thought Ubuntu was a good place. So I burned an install DVD (internal drive wouldn't work, external drive did). I tried booting it and got the same result in both drives: I clicked "Try Ubuntu" (as opposed to Install), aand it did nothing. Got the Ubuntu wheel of death.
So, I tried making a bootable usb stick with diskutil and conversions from .iso to .img, etc. Apparently my comp can only boot Mac OS X from USB tho.

So. Any suggestions?

SYSTEM INFO:
Macbook 3,1 (Late 2007)
Intel Core 2 Duo, integrated GMA graphics
2gb ram

trying to boot desktop 11.04

Did you use an ISO with "+mac" in the name? If not, here is the link to the 64bit desktop iso. http://cdimage.ubuntu.com/releases/1...-amd64+mac.iso

Also, make sure to check your iso before and after you burn it. Here is a good guide on how to do that.

https://help.ubuntu.com/community/HowToMD5SUM

Yeah. Exactly correct. *facepalm*