[ros-users] problem with ROS installation on Virtual Box

Hi everybody,
I've got problems trying to install ROS C Turtle on Oracle VM Virtual Box,
v. 4.0.0; the Virtual Box is installed on Windows XP sp3.
I downloaded the appliance (ubuntu_10.04_ros_cturtle) from ROS.org
website, but as I load it the VM Manager crashes.

Any idea?
Could be the image file (.vmdk) corrupted?
I got from the website that its size should be 2.5GB, while the actual
file size was just 522MB (I downloaded it several times... same
result...).
Did anyone experience the same problem?

Thanks a lot,
cheers,
Lorenzo