If you get a message that says that FSX can't find a certain folder it's because you moved or deleted the missing folder but didn't delete it from your scenery library within FSX SE. You'll need to restore the files that throw that error message to the same folder where they were before moving/deleting them, or ignore the error when loading the sim, load the scenery library and delete them for the scenery list. Then, if you moved them somewhere, you'd have to re-add them to your scenery list, using the proper path. Hope this ,ales sense.
Steve