I'd need to clarify what you mean by "triggering" and "inputting" before i could be sure of what is going on. How are you entering this data? How is the calculation supposed to be launched?
There are settings on the cube that prevent calculations from running if the dataunit does not contain any data. If the zero is somewhat purged or not actually saved (for example, if you have a Save Data Event Handler triggered when entering data in a form), the dataunit will be empty and those settings might then prevent calculations from running on it.
