If you use Pocketwizards, or other devices connected to your camera: always clean the contacts.

I just had a student call with a question. Her pocketwizards were working intermittently and incorrectly.

The solution: clean all contacts. On the camera as well as on the devices and cables. Once that is done, it all worked.

And I have had this experience many times. So if anything malfunctions: clean all contacts. Even the lens: move it about a little; disconnect and reconnect. Most of the time, your problems are gone.