Hi Praveen - I am not a planning expert nor a VB expert, but I recommend you provide more details, such as the version of Analysis Office and the SP (is it 1.4, 2.0, 2.1)?
Perhaps use the camera icon to upload a screen shot and share more details.
Could the cells be locked and that is why it is not being calculated- see Martin's response in this thread? Modifying an interface (column width, cell borders, etc.)