What are the packages in conflict? Please check "Problems" tab when trying to update.
It will say what packages are in conflict(most common were libgles1-sgx-img and libqt4-test). Then "apt-get remove" those packages. This process will ask you to remove the applications depending on those packages as well.
You can check this thread: http://talk.maemo.org/showthread.php?t=64312