Even in Trusted mode world.log files may not be created inside subdirectories using file().
It seems to be a really old bug with multiple workarounds.
Code Snippet (if applicable) to Reproduce Problem:
world/New()world.log=file("logs/serverlog.txt")
Expected Results:
File in subdirectory should be made.
Actual Results:
File isn't made and log text is displayed in the world output.
Workarounds:
var LOG
world/New()LOG=file("logs/serverlog.txt")