i think apt-get update and after that apt-get upgrade should solve your problem. update mine with the same method.

edit. i also faced the same issue. if the problem only persists with multiboot image then try this if you didnt installed it before. open terminal type:
root
apt-get install multiboot when multiboot installed successfully the type
apt-get install kernel-power-bootimg

if you are just updating it then use the above procedure it will work for you for sure.