How can I boot my [encrypted] System from a cdrom?

[BarbedWire]

Hi folks.

I recently installed Gentoo on my Desktop PC and encrypted the harddrives following this guide. I then realized that my Desktop can't boot from usb-stick so I thought of booting from cdrom which in my eyes would be basicly the same. Could someone please tell me how to do that? I tried to create a bootcd with isolinux following their instructions but after a short time the bootprocess stops with an error message. I don't think theres much wrong to this but I don't know where to make a change. I posted in the guide-topic mentioned above but got no answers there. You can find my error message and the relevant stuff there on page nine. Sorry for not quoting everything here again.

Thanks in advance!