I had the same problem with my Ownuser GH2 grip that I received in the mail last week. My batteries were fully charged and 100% genuine Panasonic brand batteries. When I contacted Ownuser's Customer Service, they immediately shipped out a new Ownuser GH2 grip that I am currently waiting for.
[i]"Dear Ivan,
Sorry for making your inconvenient. Due to the electronic parts Panasonic using, there is some of GH2 camera recognizing batteries extremely strictly. We're working on it but unfortunately only got little improvement so far because of the physical construction of Panasonic GH2. If possible please send the one which with problem back to us. We've sent you a new one, and the tracking number is "xxxxxxxxxxxxxxxxx". You can track it via Chunghwa POST (http://postserv.post.gov.tw/webpost/CSController?cmd=POS4009_1).
We apologize for this once again!
Best regards,
Ownuser Customer Service"[/i]
I put the "xxxxxxxxxxxxxx" to block out my tracking number.
Their "We apologize for this once again" is in reference to the original grip they sent me being stuck in customs for a week.
Hope this helps.
-Ivan