Your code is wrong.
-Set Scroll X to ITSELF + 120 * dummy.dt. You were basically setting it to 120 every tick.
-You got the lerp() parameters mixed up: swap x and b.
-Remove the scroll-to behavior from the dummy object.
-Make the dummy object global.
-Make sure both layouts are using the same event sheet. Better yet, make every layout use a "GameRoom" event sheet and "include" a room transition sheet in that one.
https://dl.dropboxusercontent.com/u/105 ... ing_1.capx
This should get you back on track.