@Wiese2007 & @Drotten,
from @Wiese2007 SH log file
Could not find hash for module "custom_citizens".
I've seen this bug before... I don't know what really causes it. But it will stop the mod from loading. That is why @Wiese2007 is experiencing trouble. It's something to do with previous versions of the same mod.... at least in my experience with it. that may not be the case for you though
@Wiese2007 try extracting the mod's files to your mods folder, (then remove the .smod) . See if that makes a difference.
Other than that fiddle around with file...
Remove the mod, run SH, add a folder called "custom_citizens", add a manifest that doesn't specify anything other than that it require to be a valid manifest.
Try even just adding in other files with the same name, run SH, remove the files...
Things of that nature.
Like I said this happened to me a while ago... I just got frustrated and renamed the mod completely. That seemed to correct the issue.
Thinking about it, perhaps someone could file a bug report for Radiant to take a look at. I don't know if there is a topic about this.