I am really just taking a shot here, but it looks like this file contains a lot of textures required to build the global environment.
I am uploading the file for you here:
www.ardst.nl/dump/WORLD.CAB
Give it a few hours after the time of this post (19:52 GMT) to finish uploading as the file is 200+ MB in size.
Download it, save it, and use a compatible decompression program, WinRAR, Winzip etc, to extract the file.
Select the following folder as as target location, and do not forget to select the "Use Folder Names" option.
..:\Program Files\Microsoft Games\Flight Simulator 9\Scenery\World
All files will be extracted to that folder (just to state the obvious) so if you want to be safe, back up this folder first (although chances are, that folder is empty in your case, if not non-existent)
If anything were to go wrong, simply delete everything in ..:\Program Files\Microsoft Games\Flight Simulator 9\Scenery\World\ and then place back the backup you made.
Good luck, let me know if it worked out 🙂