The first error is simply because you are using a H2 database but the h2 jar is not in your classpath. You should make sure the database driver jar is part of your classpath. (Updating the slf4j seems to have caused another issue so that the first issue doesn't show up yet, probably because you need to update all slf4j dependencies to the new version if you update one).
The Drools build system builds an eclipse artefact that is a local update site. So you can always download that and use it to install the latest snapshot version. But I suggest you download the latest Drools 5.2.M1 release, that works fine with jBPM 5.0.0.
http://www.jboss.org/drools/downloads
Kris