how come i am getting this?

~ $ sudo gainroot
Root shell enabled


BusyBox v1.10.2 (Debian 3:1.10.2.legal-1osso30+0m5) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/home/user # apt-get --reinstall install kernel-power=1:2.6.28-10power47 kernel-power-modules=1:2.6.28-10power47 kernel-power-flasher=1:2.6.28-10power47
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Version '1:2.6.28-10power47' for 'kernel-power' was not found
/home/user #