Thanks, everyone, for the input. I'm still going to visit the site at the link, when RW events slow down.
This is a payware aircraft, and I'm not dickering around with something like that. I just wanted to see if what I had installed in FS9 would work in FSX Accel. Actually, it does, with the exception of that prop disc. The aircraft in question has versions made for FS9 and FSX. The brand name of the aircraft has changed from what it was called in FS9, but it's still essentially the same thing. Some of the FSX repaints for it are in .dds, and some are in .bmp. The name of the texture files in all texture folders, FS9 and FSX, are the same except for the texture type.
The quick way out of this is to just pick up the FSX version of the aircraft and then maybe do some texture conversions if possible - or necessary - for the FS9 textures.