Why is my gmail notifier acting stupid?

For 6 months or so, my gmail notifier is notifying me about very old e-mails that are still marked unread. It’ll notify me that I have 1/1 new e-mail or 1/2 when I have 60 or more that are unread. I’ve already tried uninstalling and installing. Any ideas?

Running Safari 3 on 10.4