The installer refers to http://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/trunk/target to download artefacts from.
Due to changes in the Drools build, this URL needs to be updated to http://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/target

To resolve this issue in CR1, simply open jbpm-installer/build.properties and update drools.url property
drools.url=http://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/target