No, it means you presently don't have a program set to open such files that is able to. That's why I recommend getting VLC & set VLC as the default program to open your video files. If you come across other types of files with blank icons, let us know & I'll tell you which program is required to open them.

eg: I moved my iTunes music library to an external drive. I also moved the iTUnes program to the external drive. When the external drive is not turned on, all my music file icons are blank. That includes on LW & any on the computer. I have other music programs but because iTunes is set as the default to open them all ... without iTunes being available I get the blank file issue. No biggie for me. Once I reconnect the external drive the icons change back to normal.