Answer: If you just installed a new clean operating system and/or video card, it probably came with DirectX 10 or DirectX 11, if you even chose to install DirectX. It probably didn't come with your operating system.
You need to download and install DirectX9c directly from Microsoft. Don't worry, it won't overwrite your DirectX current version, it will only add older components that FSX needs to display it's objects correctly at night.
(Discovered from recent personal experience. No other changes to your Display Settings or FSX.cfg file needed to get your textures working, just DX9c)

Randy Cain