This effect comes from the update reminder application which got installed with Reader 9.
If you still have Reader 9 installed, open it and deactivate all update notifications.
Or you may also run the uninstaller for Reader 9; it should get rid of it.
If that fails, try to find the process, and/or the Registry settings which control it.
It might be necessary to completely uninstall any Readers you have, and then install Reader XI again.
Hope this can help.
Max Wyss.