Solution:
1. Unsubscribe ALL of the LOTUS workshop and check if the workshop download folder is completely empty (Steam\steamapps\workshop\content\370350)
2. Start LOTUS once and close it
3. Check if a wsitems.cfg has been created in the config folder. Well, delete the wsitems.cfg and continue with the next steps.
4. Subscribe one thing from the workshop and wait until Steam is done with the download.
5. Start and close LOTUS again
6. Check again if a wsitems.cfg was created in the config folder. So you can subscribe to the rest of the workshop objects without any problems.
Important is that after subscribing to a workshop object ALWAYS start LOTUS before you open the map editor!
