I'll assume that your Ladder Area is colliding with the ladder.
Let's look at an example...
I'll assume you understand that this is a top view of three ladders and three ladder areas. The one on the left is incorrectly placed, because it is within the ladder. The other two are correctly placed, as there is nowhere for the Player to collide with any entities/static objects which will make the character "fall" off the ladder.
I'm assuming that's the problem, but there is also something else...
The middle ladder is incorrectly placed. It's LadderArea is far too high, which will cause the player to "float" above the ground for a brief, scripted moment when the player walks onto the ground. The other two are correctly placed. The one on the right is correctly placed in both criteria.
Hopefully this addresses it
EDIT: Also, there is a smaller set of arrows within the LadderArea, which do not move the box when clicked on. These serve as reference co-ordinates to determine which way the Player will face. Assuming it follows the same ways of the PlayerStart area, the Z co-ordinate is the blue arrow, which will be the way the Player faces. If so, make the blue arrow face the Ladder by rotating the box