Kubrickr problem

When I ask Kubrickr to “crop” the image I’d like to use for the Default header, it presents in a new window a black blob with the grey border instead of the “blue blob” w/ grey border. It does not show the image I’d like to replace the Default header. My image — a jpg with just text that I created myself and uploaded to Flickr — appears correctly within the crop window on Kubrickr’s “Step 3” page. Any advice?

Thanks.