error with package manager ubuntu 8.04.1

when i try to download and install any thing with synaptic pckage manager or update manager i get this error

Ubuntu 8.04.1 64 bit

E: dpkg was interrupted, you must manually run 'dpkg --configure -a' to correct the problem.
E: _cache->open() failed, please report.

 

Why not do what it says?

 

im brand new to linux just installed it yesterday so i dont know exactly what to do

 

open a terminal.. and type

Code:

sudo dpkg --configure -a
sudo apt-get update
sudo apt-get upgrade

then try add/remove again