I'm trying to use the latest version (from SVN) of the maven embedder (2.1.x development) with AppFuse. In this version, the warpath plugin fails because the dependencies on StringUtils and SelectorUtils provided by plexus-utils are no longer provided with the embedder artifact (in fact, they are, but the package name now starts with hidden.org.codehaus.plexus.util).

For compatibility, it might be enough to have an explicit dependency on the artifact:
        <dependency>
         <groupId>org.codehaus.plexus</groupId>
         <artifactId>plexus-utils</artifactId>
         <version>1.1</version>
        </dependency>

If that wouldn't solve the problem, another (less elegant) option would be duplicating the code for the methods used in the warpath plugin.
http://fisheye.codehaus.org/browse/plexus/plexus-utils/trunk/src/main/java/org/codehaus/plexus/util/SelectorUtils.java?r=1106
http://fisheye.codehaus.org/browse/plexus/plexus-utils/trunk/src/main/java/org/codehaus/plexus/util/StringUtils.java?r=1106