'Broken pipe' error when starting a vm

Occasionally get an error 'libvir: Remote error : cannot send data: Broken pipe' scrolling down the screen when starting a VM. VM does not start and end up having to reboot server to be able to get vm going again

virsh -q -c qemu:///system start dev32
libvir: QEMU error : server closed connection
libvir: Remote error : cannot send data: Broken pipe
libvir: Remote error : cannot send data: Broken pipe
...last line keep being printed every second or so...

Trying to then use virt-manager produced the attached log file

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 10.04 LTS
Release: 10.04
Codename: lucid

$ dpkg -l | grep kvm
ii kvm 1:84+dfsg-0ubuntu16+0.12.3+noroms+0ubuntu9 dummy transitional pacakge from kvm to qemu-
ii kvm-pxe 5.4.4-1ubuntu1 PXE ROM's for KVM
ii qemu-kvm 0.12.3+noroms-0ubuntu9 Full virtualization on i386 and amd64 hardwa

# cat/var/log/libvirt/qemu/dev32.log
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 768 -smp 1 -name d
ev32 -uuid 4eb67c83-8e6a-ba91-5741-6789da4e4004 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/dev32.monitor,server,nowait -monitor chardev:monitor
-localtime -boot c -drive file=/srv/vm_disks/dev32/disk0.qcow2,if=ide,index=0,boot=on -drive file=/home/dferguson/Disk_Images/MS_Win7Pro.iso,if=ide,media=c
drom,index=2 -net nic,macaddr=52:54:00:1b:24:fb,vlan=0,name=nic.0 -net tap,fd=35,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -paralle
l none -usb -usbdevice tablet -vnc 127.0.0.1:0 -k en-gb -vga cirrus
char device redirected to /dev/pts/5
pci_add_option_rom: failed to find romfile "pxe-rtl8139.bin"
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 768 -smp 1 -name d
ev32 -uuid 4eb67c83-8e6a-ba91-5741-6789da4e4004 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/dev32.monitor,server,nowait -monitor chardev:monitor
-localtime -boot c -drive file=/srv/vm_disks/dev32/disk0.qcow2,if=ide,index=0,boot=on -drive file=/home/dferguson/Disk_Images/MS_Win7Pro.iso,if=ide,media=c
drom,index=2 -net nic,macaddr=52:54:00:1b:24:fb,vlan=0,name=nic.0 -net tap,fd=35,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -paralle
l none -usb -usbdevice tablet -vnc 127.0.0.1:1 -k en-gb -vga cirrus
char device redirected to /dev/pts/10

# kvm-img info /srv/vm_disks/dev32/disk0.qcow2
image: /srv/vm_disks/dev32/disk0.qcow2
file format: qcow2
virtual size: 16G (17179869184 bytes)
disk size: 8.2G
cluster_size: 65536

What other information would be helpful?