apt prob

[Cheatah 0#@!^]

When i try to open "ADD or REMOVE" program from the k-menu(kubuntu
6.06) this message appears-"The APT Database could not be opened! This
may be caused by incorrect APT configuration or some similar problem.
Try running apt-setup and apt-get update in terminal and see if it
helps to resolve the problem".
when i try the apt-get in the konsole, that too doesnt work.
what is the problem