uGUI objects not Instantiate()ing in executable

I have some prefabs that are uGUI objects representing tiles. In the editor I can use Instantiate() to my heart's content, but when I run a build the items are not being created, with no errors to log output.

Here you can see the runtime's output at the top, with the editor there in the background with the game running:

I've already changed my Instantiate() calls to GameObject go = Instantiate(Resources.Load("Prefabs/TilePrefab")) as GameObject; after moving the prefabs to the Assets/Resources folder, which again works in the editor but not in the executable.

Have there been any developments on this?? I see dozens of other posts about similar circumstances with very few solutions.