fail while installing packages from apt-get install

[gokul vg <gokulvg@live.com>]

when i am trying to install some packages from terminal using "apt-get
install" command the following error is coming ,

dpkg: warning: 'sh' not found in PATH or not executable
dpkg: warning: 'rm' not found in PATH or not executable
dpkg: warning: 'tar' not found in PATH or not executable
dpkg: error: 3 expected programs not found in PATH or not executable
Note: root's PATH should usually contain /usr/local/sbin, /usr/sbin
and /sbin

Please help me rectify it.

Thank you
Gokul.G