The function "Multicut"

You could say me how I can utilesé the function “MultiCut” in the version 2,61 of Blender ?
The keys “Shift K” or the key “K”, active well the function “Multicut”, but that is after the function does not work.
The short cut keyboard for the function “Multicut” to changed summer on the versions 2,5 X and 2,6 X of Blender ?
Do not speak me of the function “Loop Cut”, “touches Ctrl R”, I know it and this not she that I want to do to work.
I thank you for your assistance to resolve this problem