How to with textures

Hi, I recently downloaded a file that will allow the cabin interior of melvin raffis metjet 777 to be changed to a more designer look. The file is titled "cablan.zip" and can be found at flight sim.com. I have tried to install as the author has written, by just copying the .bmp files into the texture folder of this aircraft. When I do this, some parts of cabin change, not all. The cabin seating remains the default colors. Can someone say how to correctly add these? I have tried to contact the author, but I suppose he has changed his e-mail address. Thank you, S.