What version of the engine are you using?

Version: 1.01

Which target are you using?

[x] Windows
[ ] Linux
[ ] Mac

Explain your issue

Basically, when i try to enter a stage in the stage editor in the mod i'm making, it throws me a error, this didn't happened before to me, and this error even happens when i make a new stage with a valid folder in a valid stages folder.

The error in question:

One of the XMLs in my stages:

A photo showing that i, indeed, have the folders in stages/cartagena: