Everytime I try to import some type of content, .mp4, .mov, .jpg, .png it says the file is invalid and then deletes it. I saw that in older versions of the program you needed to copy ffmpeg to the kdenlive folders, but I'm running 18.08.01 and it's supposed to be all set.
I'm running the x64 version in Windows 7.

With the new Kdenlive Windows versions you don’t have to copy the FFMPEG anymore. For your problem see here: viewtopic.php?f=265&t=153951#p403779