It's interesting - do we blame:
OP - for not using his multimeter very often, for having dead batteries, for telling us late that it's hit with battery leakage.
Battery Manufacturer - my money is on Duracell for the big leak.
Fluke - it's an electrically weak design and died due to a weeny transient (my initial vote, Joe killed that)
Fluke - battery compartment designed to funnel leaky battery goo right onto the jungle IC and kill it.
Fluke - Repair/Calibration is impossible, resistance is futile, you will be assimilated. Just buy a new one USD $156
Leaking Duracell, they did cough up $40 for a new Maglite.