I can't use the GUI anymore: it dims continuously, so I can't correct the problem, or even try to understand where it is.
And from the error message I can't really understand where the problem may lie.
This came after I was just using the GUI, changed names to something less clumsy, and used for the first time reports, overview, etc. that I didn't see up to now, as they are brutally dimmed into the black of the background, like they are not something important... but essentially I only used the GUI and not even that quickly.
One of the names that I used for the strategies included a % character.
Could that be the problem?