This may be the same problem as my viera got, this is what i did.
I emailed Panasonic and this was there solution:
I am pleased to inform you that a software update has been created. The software is on a CAM module, also known as a CIM. Please refer to your user manual, under the section titled Common Interface Module, for further information regarding this if required.
Please allow me this opportunity to advise you that once you have received the CAM and the TV is updated, the CAM should be returned using the pre paid padded envelope to avoid damage.
Also, please return the CAM as soon as possible so that I may provide the same service to other outstanding customers.
Got the update within a week of this and everything now works fine.
Hope this helps.
Ian Rimmington
September 2009