can't set up the build environment for Orca on Ubuntu

[Mohammed Al-shar']

hi everyone.

I got a new machine dedicated for ubuntu. I installed
ubuntu feisty (the dvd version) and it all went smoothly.
anyway, my problem is when I issue "sudo apt-get build-dep gnome-orca" it
tells me:
e: could not open file
/var/lib/apt/lists/jo.archive.ubuntu.com_ubuntu_dists_feisty_universe_fource_Fources 
   - open (2 no such file or directory)

what do you think is going wrong? it happens with the dvd inserted  in the 
drive or
not in it, no difference. note also that pinging any internet url will work,
even if I do "ping ubuntu.com".

also doing something like "sudo apt-get update" works.

the reason I am sending to this list is that I am installing it to be using 
orca. and sorry if this is off list.

thanks alot.
Mohammed Al-shar'