DV 6.4.0 introduces the DSB as tech preview.
Modeshape exists in the DSB as well as the DV Server (e.g., Metadata Repository feature). However, to ensure there was no co-existing issues of trying to run both features at the same time, it was decided to not allow the DSB to be installed (using the installer) at the same time as the Modeshape.

Therefore, the DSB war's need to be removed from the primary JDV 6.4 image. It's being discussed if another image will be created for DSB.