KVM Guests not booting

I have installed KVM on Ubuntu Oneiric Server 64 AMD.

uname -a 
Linux myhostname 3.0.0-12-server #20-Ubuntu SMP Fri Oct 7 16:36:30 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

I tried creating a guest with the same OS. First I tried this:

vmbuilder kvm ubuntu \
--suite oneiric --flavour virtual --arch amd64 \ 
--libvirt qemu:///system \
--ip 192.168.0.100 \
--hostname myguest \
--part vmbuilder.partition \ 
--user adminUser --name fullname--pass defaultPass \
--addpkg apache2 --addpkg apache2-utils --addpkg tomcat6 --addpkg mysql-client \
--addpkg mysql-server --addpkg wwwconfig-common --addpkg dbconfig-common \
--addpkg apache2.2-common --addpkg unattended-upgrades --addpkg vim \ 
--addpkg openssh-server \ 
--mem 2048 \
--bridge br0

(for this i needed to configure the serial console separately btw)

Then this:

virt-install \ 
--connect qemu:///system -n myguest -r 2048 -f myguest.qcow2 \
-s 12 -c ubuntu-11.10-server-amd64.iso --vnc --noautoconsole --os-type linux \
--os-variant ubuntuOneiric --accelerate --network=network:default

In both cases the guest is generated successfully. Then I try to start the guest:

virsh start myguest
virst list --all

Id Name                 State
----------------------------------
4 myguest               running

Next I try to connect to the console:

virsh --connect qemu:///system console myguest
Connected to domain myguest
Escape character is ^]

Nothing happens after that. The behaviour is the same for both guests.
I also tried to connect remotely.

In some cases KVM then goes up to 100% CPU usage. Right now it is not using CPU.

When connecting remotely the console output was a bit more interesting:

Booting from Harddisk

And nothing else. Also I cannot call virsh shutdown myhost, I can only use the destroy command.

Can anyone point out any mistakes I have probably made?

dpkg --list | grep qemu

ii  qemu-common                      0.14.1+noroms-0ubuntu6.2             
ii  qemu-keymaps                     0.15.50-2011.08-0ubuntu4              
ii  qemu-kvm                         0.14.1+noroms-0ubuntu6.2               
ii  qemu-kvm-extras                  0.15.50-2011.08-0ubuntu4                
ii  qemu-system                      0.15.50-2011.08-0ubuntu4                
ii  qemu-user                        0.15.50-2011.08-0ubuntu4                
ii  python-vm-builder                0.12.4+bzr469-0ubuntu1        
ii  libvirt-bin                      0.9.2-4ubuntu15.2         
ii  libvirt0                         0.9.2-4ubuntu15.2                   
ii  python-libvirt                   0.9.2-4ubuntu15.2                                 
ii  virtinst                         0.600.0-1ubuntu1                        

The only log output I see in /var/log/libvirt/libvirt.log happens when I destroy the guest and tried to connect to the console before:

11:49:28.072: 1441: error : qemuMonitorIO:576 : internal error End of file from monitor