kvm usb problems

Binary package hint: kvm

In following the instructions on the ubuntu website for installing and setting up a windows xp domain in kvm
(https://help.ubuntu.com/9.04/serverguide/C/libvirt.html)
I've run into a bug with usb when I try to attach my skycaddie device and get windows to see it.
To try to get windows to see it, I attach the device, start virsh and do the following:

virsh -c qemu:///system
attach-device windows skycaddie.xml

then i can launch the skycaddie software in windows and it works for a little while, detecting the skycaddie.
Later on though when in the skycaddie software in windows i try to download data to the usb device, windows
(and the usb subsystem in linux) locks up. This is 100% repeatable. A simple 'lsusb' command in the linux host never returns after the windows instance locks up.

I've tried other ways to get this to work, such as using virt-manager to install the windows instance but it always results in the same failure.

I also tried running kvm by hand like this:
/usr/bin/kvm -S -M pc -m 512 -smp 1 -name windows -uuid 5c991002-e427-8a91-977a-e856a7950152 -monitor pty -pidfile /var/run/libvirt/qemu//windows.pid -localtime -no-acpi -boot c -drive file=/virt/windows.img,if=ide,index=0,boot=on -drive file=/dev/sr0,if=ide,media=cdrom,index=2 -net nic,macaddr=54:52:00:68:e2:c8,vlan=0 -net tap,fd=16,script=,vlan=0,ifname=vnet0 -serial pty -parallel none -usb -usbdevice tablet -usbdevice host:10c4:ea60 -vnc 127.0.0.1:0 -k en-us -soundhw es1370

where i added the -usbdevice host:10c4:ea60 parameter to try to get it to see the skycaddie directly but when i try to run kvm this way the image doesn't seem to want to start up.

after this issue occurs, i must force the windows kvm guest to shut down, and reboot the linux host as well. The linux host will always fail to reboot - it fails to unload the kvm_amd module and then sits there blocked on 'stopping bluetooth' at which
point i have to power cycle the box.

Any ideas welcome, thanks.