This is a UNIX permissions issue, make sure that the Enterprise Server Admin user has read/write access to the Ressource Definition files (dfhdrdat and dfhdrdat.idx).

Do an "ls -l dfhdrdat*" and make sure that the Enterprise Server Admin user is the owner of the file or part of the group that owns the files.

Also make sure that the rights on the files are at least -rw-rw-r-- (644).  If they are not issue a "chmod 644 dfhdrdat*" command to set the proper rights.