Possible fix
I had the same problem pop up last night on my Droid Incredible. I couldn’t get mail or texts, though I had more than 6G free. This morning, I read up on this and cleared data from some applications. The problem went away when I cleared the data from the Facebook app. (Note, I deleted Pandora just before that, as that was the app I was running when the problem started last night, but I think it was the Facebook app that did the trick. I reinstalled and restarted Pandora with no problem. If it comes up again and clearing Facebook doesn’t work, I’ll try uninstalling Pandora again though.)
I had the same problem pop up last night on my Droid Incredible. I couldn’t get mail or texts, though I had more than 6G free. This morning, I read up on this and cleared data from some applications. The problem went away when I cleared the data from the Facebook app. (Note, I deleted Pandora just before that, as that was the app I was running when the problem started last night, but I think it was the Facebook app that did the trick. I reinstalled and restarted Pandora with no problem. If it comes up again and clearing Facebook doesn’t work, I’ll try uninstalling Pandora again though.)