When did you charge the batteries? Eneloops and other slow-discharge batteries will hold a charge for quite a while. The non-slow-drain rechargeables lose their charge very quickly even when not in use. I had a set of 2700mAh batteries, brand new, but they drained very quickly. Eneloops and other slow-discharge batteries like
these Ansmanns work much better.
Still, even with the 1.01 firmware update, the battery meter on my Kx remains inaccurate. It quickly goes from green to that half-empty orange. When I turn the camera off and back on, it's green again for a bit. It does take quite a while before the battery meter goes red, and even then the camera keeps going. I have the battery type set to NiMH, and it's still wonky. Since the meter is clearly inaccurate, I just make sure I've got an extra set of Eneloops or Ansmanns with me. Usually the SD card runs out and not the batteries!