The 1009 error indicates that one of the objects being targeted by your code is out of scope. This could mean that the object....
- is declared but not instantiated
- doesn't have an instance name (or the instance name is mispelled)
- does not exist in the frame where that code is trying to talk to it
- is animated into place but is not assigned instance names in every keyframe for it
- is one of two or more consecutive keyframes of the same objects with no name assigned in the preceding frame(s).
Since this happens in frame 29 it gives me the sense that you have the button animating in some way in the frames prior to that. If so, make sure you assign the instance name to it in the earlier keyframes.