Please post your worksheet - there are a number of potential causes of your problem and it is difficult to diagnose the problem from just a screenshot (a screenshot is, however, very useful in giving an indication of the problem).
Having said that, I'm guessing that you've used an (Excel) component to input the data, in which case your problem may be due to you including blank rows in your data.
Stuart
Oh, forgot to add - you don't need to define i as the square root of -1. Mathcad already has that definition.
Stuart
