This seems to be a verified bug on KVM with no solution. I wasn't able to get through the installer with Ubuntu 12.04, it would crash while "configuring apt". I was able to install it with Ubuntu 12.10 but it crashes randomly at times.
This happens with the latest Centos 6.3 kernel and KVM package, I even compiled the latest version from the KVM website and used that, but the results are still the same.
Here's some links to discussion about the bugs:
https://github.com/sahlberg/libiscsi/issues/32
https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/975834
https://answers.launchpad.net/ubuntu/+source/ubiquity/+question/197304
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