I tried to skip the "NEW MOVIE SKIP" at the beginning of Chapter 2 and the "FMV SKIP" at the end of Chapter 4 on the PC version as per the guide, but without success. Can you please tell me how to make this skip work?

When you speak to Shinra and the sphere is playing then pause the buffer after the 4th red light,so only pause it In chapter 4 it's a bit different, we skip the scene with Yuna and Shuyin after the Ixion fight, to get a new buffer we have to see a new FMV which is the reassembled sphere, the sphere you got after Ormi, Logos ad Leblanc fight, we do that before we do the commpsheres in chapter 4, go to treasure spheres, and choose the reasembled sphere, we pause the buffer once the Vegnagun Head has been zoomed in which is around 40 seconds when you first play the sphere