What camera are you using? DV, HD, action cam?? Is it the camera or the media that is causing problems? Have you hooked up your camera with a usb or firewire cable and used Project/Import Media, or are you doing something else? If your cam uses a chip, have you tried to access the video with a reader? Have you tried downloading the clips to your hard drive and then importing them into Movie Studio?
Is the problem that you can "see" the files, but Movie Studio can't open them?
We can make all kinds of guesses, but if you don't say exactly what problem(s) you are having, no one will be able to do much to help.