You now have a bad save. Delete it & replace it with one from the backup folder. And that wasn't exactly a ServUO error. Your server went into save mode while trying to run the CreateWorld. Which is what ultimately caused the corrupted save.
I think that would be the best thing to do, besides, who wants to create world more than once? So it would I'd assume be used sparingly and would be the least disruptive, then you could simply end the Create world command with a save anyways since it created so much.
Lucian, in the meantime prior to this being repaired in the repo, you could probably just disable your server from saving automatically (or set the timespan to something that won't trigger like 1 day), fire it up, run create world, manually save, shutdown. Then reactivate the automatic save to your normal interval and fire it back up.
Not sure what you have before Custom Path but remove it -shouldn't be anything there if this doesn't work- Do you have a folder named just Program Files? If so try moving ServUO and the game client there .
# Uncomment this line and set it to the path of the client files to set a
# custom data path. Otherwise ServUO will look for the client in the default
# Windows installation directories. Note that this is *required* when running
# on non-Windows systems.
CustomPath=C:\Program Dosyaları (x86)\Electronic Arts\Ultima Online Classic
You need to have it use the exact path to the files, since yours is Turkish, you will need to use the same language for the path.