I've run into a WAR deployment problem that I'm hoping someone here can help me understand and resolve.

I've put together a small web application (just a servlet filter) which references Apache Commons Codec. This project uses Scala. When build with Scala 2.9 it deploys to Geronimo and runs.  When build with Scala 2.10 it does not deploy.  However, both versions happily deploy and run under Tomcat 7. 

The exception is:

ERROR [[/hello]] Exception starting filter MyFilter
java.lang.NoClassDefFoundError: org/apache/commons/codec/binary/BaseNCodec
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:266)
at org.apache.xbean.recipe.RecipeHelper.loadClass(RecipeHelper.java:52)
at org.apache.xbean.recipe.ObjectRecipe.getType(ObjectRecipe.java:353)
at org.apache.xbean.recipe.ObjectRecipe.internalCreate(ObjectRecipe.java:266)
at org.apache.xbean.recipe.AbstractRecipe.create(AbstractRecipe.java:96)
at org.apache.xbean.recipe.AbstractRecipe.create(AbstractRecipe.java:61)
at org.apache.geronimo.j2ee.annotation.Holder.newInstance(Holder.java:180)
at org.apache.geronimo.tomcat.TomcatInstanceManager.newInstance(TomcatInstanceManager.java:64)

I've put the project on github with details of steps to reproduce and the full stack trace and WAR contents:


Any suggestions for how I can resolve this one?