Once you have generated the DBD you need to generate the PSB. To generate MFDEMOs single PSB file (demo001t.psb):
Generating the PSB produces the psbgen3.dat file.
This file contains PSB source information that has been extracted and formatted into a smaller structure optimized for faster access during execution. PSB files are indexed files and can contain one or more generated PSB members. Do not edit, move or delete these files.