If you happen to find Kotobee Author's window filled completely with black and not showing anything else, learn how to fix it here.
A black screen indicates most probably an incompatibility issue with your video driver. This can be resolved by updating your video driver.
A quick workaround to have Kotobee Author working immediately, is to right-click on the software icon, and select Properties.
Select the Compatibility tab and enable Run this program in compability mode for.
In the dropdown list, select Windows 7 and hit OK.
Restart Kotobee Author. It should now open without a black screen.