Hello and Welcome. My name is Michael.
The error message that you are getting it's usually caused by "dirt particles" found on the contact connections either on the battery or inside camera itself.
It can also be caused if the battery was manufactured by a third party company other than Panasonic. If the you are 100% sure those batteries were made by Panasonic then try cleaning the contacts with a clean Q-tip and a very small amount of rubbing alcohol on the very tip of it. If all fails then certainly take it for cleaning maintenance at your local camera repair center.
If you have any other questions on this matter, be sure to let me know.