Proportions mod Version 2.5 available

[dogscoff]

invalid filename

Sounds to me like a problem with the auto-save function- probably trying to save to a directory that has since been deleted, or maybe the filename you entered uses invalid characters.

Make sure you've got a proportions/savegame and that it's not savegames. If that doesn't fix it, try to save the game manually and see what directory/ filename the savegame requester defaults to.