Hmm, something is really wrong with the networking there... It looks like your DHCP server doesn't return all the settings (DNS servers at least) properly. You're using DHCP to get the IP address for your board, right?
Try to run the wget command, which opkg claims to be failing, manually. What happens then?
I.e. run "wget http://alextgalileo.altervista.org/pkgrepo/i586/gcc_4.7.2-r20_i586.ipk&& ls -alF"