Piru is right regarding the laws of copyright.
However i suspect most of these companies would not care in 2010 if someone had an adf of that game or not.They have long ago abandoned the amiga scene.Now that does not make it legal(this is intelectual property we are talking about and the laws are very specific).But certainly i see low risk for legal actions against those that host these files.
You know something?If this thread or some other becomes the reason those companies go to courts to defend their rights then let it be!We should then know that these companies still appreciate the amiga scene and maybe after the court we can convince them to offer us upgrades or some sort of patches.(i know it sounds silly,it is a joke).
On the other hand if you want to be certain that there would be no problems then you could contact the original copyright holders (-that is if you can and if they do not delete your email like it is spam-)
Kind regards
