Cannot communicate with battery" error on 5D Mk2 with BG-E6

So about a Month ago I got the Canon 5D Mark II and it came with the 2.0.4 update ok so back to the error..
Last week I got the Canon Battery Grip BG-E6 and I also got on more Battery so I can have 2 whats a battery grip without 2 batteries right.
So when I put my battery grip on my camera and when i turned it a black screen goes on and tells me this Cannot communicate with battery and gives me the option to either cancel or continue and when i selected continue noticed that the battery level was shown empty. So I take out the Canon Batteries and use 6AA Batteries and that works just fine.
Can some one tell me how to fix this?

Is the battery Canon branded or generic?

Canon branded

I'd get it replaced. These batteries have a chip inside that communicates with the body to give batter life information. This is what happens when you use generics, which don't have that chip.

Do i replace the Camara body or the Canon Battery grip

If you can, I'd test out the grip with another Canon battery first.

Oh i send back the Canon Battery grip back and Im waiting now for a new one but the Batteries work fine when i dont use the grip also whats massed up is when I use the 6AA batteries it worked fine with the grip

Where did you get your new Canon LP-E6 batteries from ?
Does the new battery charge on the original Canon charger?
Did the BG work with just the original battery in it ?

the first Canon Battery i got was the one that came with the camera and 2ed one on Amazon
then both work with the canon charger and the original battery does not work with the Battery Grip

I've got a month old 5d Mark II w/ a Canon grip and Canon batteries (4). I also have the latest Canon F/W 2.0.4. All work just fine and communicate w/ the camera body as advertised.

I'd suspect a bad grip, bad or fake batteries or possibly corrupt F/W.

so ya i got a new battery grip just came in and it dose the same think

Do some testing with some other batteries. It might help if you find some local photographers who would be willing to swap hardware with you for testing purposes.

What happens if you only put one battery in the grip (may need to check - some grips require a single battery to go into one side or the other)?

bartsphoto wrote in post #9964647
so ya i got a new battery grip just came in and it dose the same think

looks like you have a camera body problem, I can't see how two genuine Canon battery grips could have the same problem. Where are you getting these grips from ?
Suggest you look at reinstalling the firmware. How hard are you tightening these grips ?

ya I called Canon USA today and I told that I got the camera on 03-14-2010 And I got the Battery Grip BG-E6 about last week and that one was telling me that Error Cannot communicate with battery and gives me the option to either cancel or continue and when i selected continue noticed that the battery level was shown empty so I took back the grip and the new one came in today and i tested it out also but that one did not work also. I am like but the Batteries work fine with out the grip and the funny think is that when i Use 6AA batteries in the Grip it works fine. SO they guy put me on hold to test out that on there cameras but he was not getting any errors So he ask me for my info and my email so he can message me on where to send the camera to. So how i have to send in my New canon Body thats not 30 days old yet also I have to send in the battery grip with all my batteries. And I still don't know If i will get my camera back or a new one , or yet better a Refurbished one I just hope Not a Refurbished one. like i sad i just got this camera not a month ago.