I've loaded an STL file. I've voxelized it. I click "file -> export -> simple stl file" and get the error "No object selected. Please select a single voxel object to proceed" I click "ok" and of course nothing happens. Here's a screenshot (or not, once I'm not a new user I'll upload a screen shot it appears).
So, how do I select a single voxel object? Or is there some other problem there?