The ladder may indicate access to high places in this life or access to special places in the universe. It is also sometimes an object you fall from when you have dreams that include the falling sensation.
The central idea of a ladder is gaining special, albeit precarious, access to other places. Such access often carries with it the possibility of a dramatic loss of ability or favor with the prevailing influences of the situation.
If you are in a situation that requires you to obtain a ladder, it may be that you see yourself as inadequate in your current means. The limitations of height and gravity are acutely felt in this world. If your dreams do not offer you the possibility of flight, the ladder is often the only solution to the problem.