Sounds like you need new auto update files. The cable company sends out keys along with all the channels, you need these keys to view the premium channels. A program runs on the box to grab the keys from the stream and it uses them to show you the channels. The method of grabbing the keys changed on 8th April so you will need new files to make it work again.
You will need to connect your dbox to your PC in order to transfer the files to the box. You will need a crossover ethernet cable (£3 from ebay) to connect the dbox to your PC.
You will get the files you require here...
For those still having problems with auto updating...read here
And there's a guide for connecting the dbox to your PC here...
It's for a dreambox but it's exactly the same for a dbox2.