After I load a city and play for around 10 seconds, i get the next message:

Escrito originalmente por AN ERROR HAS OCCURED:

Object reference not set to an instance of an object [System.NullReferenceException]

Details:
No details

After some time, this message appears again.
After even more some time, it starts to constantly spam these messages, rendering this game unusable.
How do I fix this problem whitout checking out all of my mods?