shanmukhateja; Hi !
I will take my stab at this:
1st -> "ubuntu-13.10.SMALL.ext4.img"; release 13.10 is End_Of_Life and has no support, thus I can believe supporting libraries are no longer available.
2nd -> you say "found out that it was missing apt-get and dpkg. Can anybody tell me " ; Well those come installed as default applications on every linux distribution - that I am aware of -.
Check and see:
3rd -> why do the vncserver the hard way ? Those tools are available in the software repository !
dpkg -l apt
dpkg -l dpkg
apt-cache search vncserver
let's see where we go from here