Need Help with FF3 Level Editor

Hey guys I have a quick question - I'm trying to modify Narshe to look a little more open and not so closed-up for my hacked ROM. So using FF3 Level Editor, I erased that little over gap thing that Terra, Biggs, and Wedge first walk under right when you gain control of them. I understand that that overgap is in layer 2 so I was wondering, with the overgap gone, is there any way to place a walkable tile where it once was so they can just go forward? The reason I'm asking is because, I copied the tiles below Terra right when you gain control, and the pasted them where the overgap was. Thinking all was good I loaded up ZSNES (Level Preview doesn't work for me ) but whenever I got to the beginning of Narshe, Terra is just stuck and can't move in any direction. It's really confusing and I would greatly appreciate help. What I'm really asking is if it's even possible to place a walking tile where a layer 2 tile used to be.
Thanks!
xJCSx