First, go to
Easy URPMI, and set up your sources correctly. If you did not do so the first time, make sure to set up all sources for both the 'Official' and the 'Penguin Liberation Front'(PLF). PLF contains software which is not released under the GPL (not Open Source).
Second, open a terminal window, and su to root. Remove any existing sources:
urpmi.removemedia -a
Third, one at a time add the corrected sources you just created at
Easy URPMI.
Log out from your session (End current session), then log back in.
HTH,