[ubuntu] KVM - ISO Booting Issue

Hi,

I'm trying to boot an ISO of ubuntu 12.10 in a VM I have made using KVM. I'm trying to do all this through the Virtual Machine Manager. I copied the ISO to /var/lib/libvirt/images/ via a local ftp and have attached this to the virtual CD Rom. However, on startup I just see 'Boot Failed: Could not read from CDROM (code 0004).

I couldn't find much about this online which was helpful to me. If anyone has any ideas or needs further info, I would be very grateful for your expertise!

Thanks