"X" in result row when summing up hierarchies

Hello,

we are on an SAP BW environment in Analysis for Office 1.4,  in the result row, we get "X" in  a summary field, I suspect it is trying to sum up a "blank" row. If this is the case, is there a way to change "Blank" to "0" so the numbers sum up properly instead of "X" in "Analysis for office" or does this have to be done in the "BEx query"?

If "X" represents something else, please let me know how get the results row to summarize properly?

Thanks