In my game, I have blocks setup as being breakable or just normal.

Depending on which ones I make breakable, when finishing the level and trying to free the stuff up, I get an access violation error on the first breakable object it tries to free (but the error seems to happen before I even check if the object is dead or try anything on it).

I tested by sticking a ShowMessage in there to see where exactly it fuddles up, but it never shows, it only shows the error (this is in a for loop).

Is there any good methods of narrowing this down and finding out what on earth is going on?

Considering if I change which ones are breakable, it will work with some configuration but not others, it's a tad confusing.