Building the project archive something.ear that contains multiple compressed archives, for example something.jar (ejb components) and something.war (web components) it always fails with internal error caused by the null pointer exception.
Note, that building the project archive in exploded version is finished without problem.
I've seen that some tickets had been created for 2.1.0 GA for building the ear of SEAM type of project. I have met the problem for typical build of ear contaning one jar and one war compressed archives.