This is makeindex, version 2.15 [MiKTeX 2.9.6500 64-bit] (kpathsea + Thai support).
Scanning style file C:/Users/paarl_as/AppData/Roaming/MiKTeX/2.9/makeindex/deltares/deltares_nomentbl.ist...............
** Input style error (file = C:/Users/paarl_as/AppData/Roaming/MiKTeX/2.9/makeindex/deltares/deltares_nomentbl.ist, line = 51):
   -- Unknown specifier \endinput.
done (15 attributes redefined, 1 ignored).
Scanning input file dflowfm_validationdoc_AP_tabulated.nlo...done (0 entries accepted, 0 rejected).
Nothing written in dflowfm_validationdoc_AP_tabulated.nls.
Transcript written in dflowfm_validationdoc_AP_tabulated.ilg.