ubuntu installation fails on package database update

[noam2003 at speedy.co.il]

I tried to install ubuntu several times, and every time it gave me an error message while
installing the base system. after a few times I decided to check when it occores, and I
found out that the poblem occors while updating the package list from the internet. the
installation program has managed to configure the internet connection via DHCP, and the
disc is vaildated.

a. what could the problem be and how can I fix it?
b. how can I skip the updating
step?

____________________________________________________________
                                ñôéãé-ðè, äàúø ùìëí áàéðèøðè
http://www.speedy.co.il/