Unable to install Ubuntu in VirtualBox OSE

[Mark Diekhans]

Hi Folks,

I am trying to install Ubuntu in VirtualBox OSE and hitting
a wall:

Configuration:
    FreeBSD 8.1-RELEASE amd64 GENERIC kernel
    virtualbox-ose-4.0.10
    virtualbox-ose-kmod-4.0.10
    Using remote X11 access, not a local server
    no special virtualbox configuration changes

Tried both:
      ubuntu-11.04-desktop-amd64.iso
      ubuntu-11.04-desktop-i386.iso

Makes it to timezone selection screen and VirtualBox machine
aborts and machine window closes.  No messages are added to the
log after the install starts.

Any ideas?
Thanks
Mark