To expand on redazz' post, visit
EasyUrpmi and set up your package repositories. Then you can use urpmi (or the Mandriva Control Center/rpmdrake) to fetch any packages you need, along with their dependencies.
kile 1.8.1 is available in the "contrib" repositories for Mandriva 200
6, if you care to step up. Otherwise, just get the libkdecore4-devel package from the 2005 repositories.