Update Brain and all its dependencies to Scala version 2.11.
ProgramD (a Brain's dependency) is having trouble reading xml files (xmlns issues). So, for now you can only model the knowledge base and export it to AIML files, but you can't test the chat itself directly within Brain. In the next few days Brain will use ProgramAB (for AIML version 1.0.1, still) to enable this feature again.