Your scenery.cfg was ALREADY corrupted before the installation, and contained a syntax error which, as explained but the error message, was around the line of the scenery area 101.
The error is probably a result of having edited the file manually. In this case, you probably have the Area number on the same line of the Title, because when you hand edited it, you forgot to add a Carriage Return...
FS9 is quite tolerant to those errors so, it might have just skipped the area (you probably have a duplicate that works), but the installer parser expect the scenery.cfg file to be clean of errrors.
If it's not, it will notify you (as it did), so you can fix the error.
But the scenery will not show up until the installation can complete without warnings because, obviously, if the scenery is not added to the scenery.cfg, it will not be displayed (this is valid for any scenery), and the scenery.cfg is not touched if errors are found inside, which were already there before the intallation.
