I can assure you, it's very unlikely that you actually burned 2400 calories doing massage. The problem with tracking work activities as exercise is that the more we do something, the more our body adapts to it. Your work duties are something you do all the time, and because of that, your body is more efficient at it than if, for example, I jumped in there and tried to do it.
You should only track purposeful exercise in your tracker. It's intended for use only for those extra exercises. Your Sparkpeople calculations include a daily active living modifier that includes things like running errands, working, and doing things other than lying in a bed living. :)
If you have a particularly active job, you can figure out how to add more calories to your range here: www.sparkpeople.com/community/ask_the_expe
You are most certainly burning calories, but not enough to improve your fitness level or really count as exercise.