Your package plexus-active-collections either requires or buildrequires plexus-container-default. This package contains old API which is not commonly used and has not contained maven dependency mappings since September 2011. It means that unless your package is using custom dependency map to build, it is not using plexus-container-default. In most cases your package is instead using 'plexus-containers-container-default' package. If any pom.xml files contain reference to groupId:artifactId org.codehaus.plexus:plexus-container-default you can replace plexus-container-default with plexus-containers-container-default. If your pom.xml files don't reference mentioned groupId:artifactId it should be safe to remove completely
plexus-active-collections-1.0-0.9.beta2.fc18 has been submitted as an update for Fedora 18. https://admin.fedoraproject.org/updates/plexus-active-collections-1.0-0.9.beta2.fc18
plexus-active-collections-1.0-0.9.beta2.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.