SODE installer gave you the most important suggestion: there's a problem with the SimobjectPaths lines in your FSX.CFG.
It's possible your FSX.CFG has been corrupted. The most common reason for this, is that you (by hand-editing) or another defective addon, has corrupted the FSX.CFG file, removing a default section that must be there, in order for the sim to find the scenery objects and many other library objects used by default scenery.
Check your %APPDATA%\Microsoft\FSX.CFG file and and look all the lines containing this:
SimObjectsPath=
Be sure all the numbers are in sequence.