I take it you have a DirecTiVo, yes?
Check your "Channels I Receive" list. In the past there has been the occasional bug which un-checks all your channels, which makes the TiVo "think" you don't get any channels. The guida data is still on the hard drive so re-checking the channels usually fixes it.
If that doesn't do it, go into the menus and find "Restart the Recorder". Follow the instructions and reboot it.
"Bush wasn't just a Republican president, he was the Republican president. He went to bat for every idea that ever got the official elephant nuts seal of approval. The record that resulted isn't just a measure of Bush's incompetence, it's a measure of just how bad Republican ideas are in practice." - Devilstower @ dailykos.com