Crystal keeps renaming and moving the developers help file from version to version. Perhaps as some sort of inside joke.
From a support document:
For Crystal Reports 8.5, the Developer's Help file is:
CrystalDevHelp.chm
and is installed in the default location:
C:\Program Files\Seagate Software\Crystal Reports\Developer Files\Help
For Crystal Reports 8.0, the Developer's Help file is
Developr.hlp
and is installed in the default location:
C:\Program Files\Seagate Software\Crystal Reports\Developer Files\Help
For Crystal Reports 5, 6, and 7, the Developer's Help file is
Developr.hlp
and has a shortcut listed in the <Seagate> Crystal Reports program group under the Start menu.