Hi and welcome
maybe your package list is outdated, or there is some packages conflecting with the one you're trying to install.
if you want the fast way, you can install "faster application manager"
for a manuall download you can visit http://repository.maemo.org BUT be carefull what you are donloading

and please consider using the power search button before creating new threads and you also might want to read the wikis http://wiki.maemo.org

enjoy

./sifo