Pivot Table Calculation

I've made a calucation in my pivot table but when I do so, all the data is subjected to the calculation and I end up with a lot of #DIV/O! errors on my screen. Is there any way to exclude the data that contains zero's in the calculation? Or to just hide them in general? I've already suppressed zeros in the data that I'm using for my pivot table, but the calculation is including all of the values to apply to this calculation.

And how can you make a calculation follow a certain format, such as percentage?

Ok now I don't have anything showing where an error was before but is there anyway that I can remove the row entirely since it does not apply to my data? Such as suppressing zeros in all rows, is that possible through an excel pivot table?

And I can't format a calculation? Is there any way around this?