Textures disappear - pitiful misperfection.

[SWAFO]

To me it sounds more like an issue with FS, as opposed to FSP. FSP does not interfer with textures at all, and from what you're
describing, it seems like your textures simply aren't loading on top of the model (all FS9 related). Do you give it some time to load?
Occasionally large textures can be quite taxing on your system, and might take a while to load.

I'm guessing that your issue isn't FSP related. You might want to try removing/re-installing some of your current textures that are causing
problems, or simply removing and re-installing FS9 altogether. This seems to fix most issues.