For the tilesets...
Open your Database under the Tools tab.
Go to tilesets.
Select the new tileset.
See how there's a preview of the tileset to the right? Notice all those "O"s on each tile?
That's the passability. An O means you can pass threw it. An X means you can not. Change the tiles you don't want passed to an X.
The other tabs can help you, such as Passage (4 dir) which is like the passability, but limited to only certain directions (could make it possible to move down a tile, but not up, etc). You'll also have to play with the Priority setting, which is what causes certain tiles to appear over (above) the NPCs like the tops of trees and the like. Higher priorities are set for that.
Dunno about new song, title, and what not I've never had, or came across someone who has had that problem.
Hope that helps, somewhat with your post, and good luck.