Hmm... that's a tricky one! I've done many things to FS9 that have resulted in a lack of textures (there's nothing quite like flying a grey plane over grey land through a grey sky!). If the textures are only refusing to appear during instant playback I'd suggest your computer's struggling to load them for some reason - it sometimes happens to me when I'm overly ambitious with the scenery settings! I'm afraid trial and error has been the main solution to problems like this for me, so unless someone else knows (which I'm sure they do - there are many people on here far cleverer than myself) I'd suggest perhaps trying with different aircraft in different places with different settings.

Sorry I can't be more help!