If you try to unpack a manage server template and get an error telling you that your unpack command failed.
Take a look at the log file located under your $MW_OME/log directory starting with a name like unpack_<today's date>.log.
The log file will tell you exactly what the problem is. In my case, I was recreating the domain and the application directory already contained the application.
The application directory needed to be empty.
Error : fail: write Domain to