And there's the reason why I avoided doing it until I was informed that having the spaces was causing an issue. Thank you for bringing this to my attention.

Unfortunately, moving forwards, the _s will have to stay. It is my understanding that having spaces in the filename can cause issues with running mods on the server (hence the mod error). For existing games, feel free to replace the _ with a space in the filename and the first line of the mod (that is #modname). You should also be able to revert to the July 4th version from the Change Notes tab for the same effect.