Neal -
even a freshly charged battery can give problems if it is old. Anything older than 18 months for these NiCD battery packs is old and time to replace. A good alternative that I am using with my D1H is the battery from Delkin. They are half the price of the Nikon batteries and they are a higher capacity so they last a bit longer.
As for the lock-up problem, it can be caused by bad batteries, and another possible cause for this is that if you change lenses without turning off the camera first you can get some weird problems with the body. Of the original four D1 cameras that our paper had three of them got flaky if you swapped lenses without remembering to shut the camera down first. A real pain for me as I swap on the fly quite a lot, or I did when I was just shooting with one body.
Jeff Jones
The Gallup (NM) Independent