This is not a program error. The reason you can’t save as jpg is because you clicked the button to run a batch for cutout images. The JPG file format doesn’t support transparency so you can’t save cutout images as jpg. If you are running a batch for images with transparency then you have to save as PSD, TIF, or PNG.
If you are running a batch for images that are not cutout then choose the option to run the batch for non-cutout images. So go back to the Face Crop home menu and choose non-cutout batch