Create an empty folder in "/usr/pluto/orbiter" called "bits"...
sudo mkdir /usr/pluto/orbiter/bits
...and then create your orbiters in the normal way http://wiki.linuxmce.org/index.php/Web_Orbiter_2.0 (thanks Thom).
I understand a fix is being prepared, but just thought I'd mention this workaround in case you can't wait.
Cheers,
Matt.
EDIT: This was also mentioned here http://forum.linuxmce.org/index.php?topic=11825.0