Translation:You cannot do it without permission.
Consider alternate translation 'You may not do this without permission.' In many situations it may be physically possible to perform an unathorized act.
Does "pozwolenia" mean both abstract "permission" and concrete "permit" (as, for example, a building permit).
Happens more and more recently, the forum is buggy. Yeah, double meaning :)
Could, "you are not allowed" to do that, also fit? or would that be expressed differently in Polish?
You could also say, "nie wolno tego zrobić", or "nie wolno mi tego zrobić" if you want to emphasize yourself. Right?
In your construction, I'd rather say "robić", "zrobić" here is a bit like "Just be careful not to do X by any chance!". Your sentences sound more like "It is not allowed to do it at all".
And the first one doesn't emphasise myself, it just states that it's not allowed for anyone. The second means that I am not allowed.