I don't think it's your fault. From what I know, I believe that Google sometimes has some issues with their servers that get the page ranks connected to people's computers. Their servers with the PR information might be down, but usually it is only a matter of minutes before it starts working again. Or at least that's my case.
And yes, the Google deskbar has been out for about two or three weeks from what I know. I read about them releasing it at another forum, but forgot to post it in this forum.
