Homecrafter Issue - Black Screen of Death

I am trying to make some very basic CC content which are walls (first time making them). But, where walls are supposed to be, it's just black...

Here is a screenshot of the problem: http://i.imgur.com/AKKYaem.jpg


Help?

I have tried restarting Homecrafter and restarting my computer. This problem is happening with all the walls I have made.

I made my walls, put them in the folder (folder location shown above in screenshot) and then the black screen of death happened.