See posts 9 through 11. I have been meaning to find this myself. Thanks for reminding me. I assume this will keep the error from popping up when we fail to upload all of the images, such as multires. I have seen my server fail to save the images or my ftp software fail to upload a few tiles, yet without the error messages, I would never know since it appears that the other levels take care of the issue. Maybe I am wrong, perhaps I do have a black spot somewhere in the few panos that this has occurred.
One thing to note, if you have a progress bar, and for some reason, all of the tiles cannot be found by krpano, the progress bar never completes and goes away.