The Penguin Subtitle Player Linux binary is built with libpng12-0, which isn't available in Linux distributions for a long time. For example Ubuntu 18.04 (released two years ago) doesn't have it.

When trying to run it I get (and everybody else using a not very old Linux distribution):

./PenguinSubtitlePlayer 
./PenguinSubtitlePlayer: error while loading shared libraries: libpng12.so.0: cannot open shared object file: No such file or directory

Linux distributions nowadays use libpng1.6 (libpng16-16), so please build the Linux binary using this.

Thanks!