There are multiple things you can try.
One item is to try and keep the name of your transform to follow 8.3 notation. For some reason SMS will on ocassion have problems with long file names.
Another thing to try is use the TRANSFORMS option as before, but use the full path to the transform. I have had problems at times where SMS does not source back correctly and cannot find the transform. In most cases, giving the full transform path seemed to fix this issue.
I hope on of these ideas helps.