WWT 5.5 encounters problem

I just installed WWT 5.5 and it does start up but as soon as I deselected the submenu-option “Planets (NASA ETAL)” in the menu-option “3D solar system” I get the messagebox “WorldWide Telescope has encountered an error. Click “OK” to restart or “Cancel” to attempt to ingore the error and continue”. No way to ignore this; one get stuck, Clicking “OK” results in a restart and all starts over again.