Initially, I was sending TIFF and RAW files from LR4. I discovered the problem was that I was exporting as 16-bit depth files. I changed the export function to default to 8-bit. That cleared up the problem. Thanks.
In 16 bit color mode you are not allowed to add more layers.
Instead of going back and change the export option to 16 bit, you simply go to Image menu > mode > 8 bit/channel . It will change the bit depth to 8 bit .
Europe, Middle East and Africa