Ok, first point is that the compiler doesn't throw exceptions - they happen at run time. So the problem is not that the compiler doesn't like the code, but that the code is doing something wrong :) Can you tell us which line of the updateImage() method (as posted above) corresponds to line 9 of the class (i.e. which line actually throws the exception)? Note that getWorld() returns the world the actor is in, not just "the world", so if the actor hasn't been inserted into the world yet then getWorld() will return null.
