With the MB-D200 attached to the D200, sometimes I fail to shoot.

Recently having intermittent failure with a variety of lenses attached and shooting in all modes. I depress the shutter release and get a "Err" message and no exposure. Have to press it again to release it. Sometimes it works and sometimes it doesn't.

I just took the MB-D200 off and was successful without any misfires. Is this a power problem caused by the MB-D200? I noticed one of the batteries has been discharging much faster than the other too. Could it be a bad battery?

The battery meter on the camera is showing a full charge when the MB-D200 is attached. However, when I remove it and place the individual batteries in the D200, one is full and the other is almost empty.

Should I buy another battery and see if that corrects it?