mediaserv refuses to play video files which are stored in directories with spaces in their names. Mencoder can be seen doing it's work, but attempting to play the video results in Media Player stopping immediately as soon as you try to play it.

Spaces in the video filenames themselves work fine.

Everything stored in my /Movies/ directory plays perfectly. Everything in /TV Shows/ does not. Moving a file I've attempted to play into the root of my share directories allows the video to play fine, even if it didn't work in the /TV Shows/ directory. So... as far as I can tell, it's a problem with spaces in the path to the video file.