Hi,
Try creating a zip file to lessen file size (or remove some data rows). File size limit is 1,024,000 (1 MB or 1024K).
Having not seen the data yet, let me toss out one guess: when this happens to me it can be the case that there is a one-to-one relationship between a record in the fact table and a record in the calendar table and, when making the connection, I dragged from the calendar table down to the fact table (not from fact table up to calendar).
If my guess does not apply, looking forward to the smaller size file.