How do you write an MDX query so that the cells you can't access return empty (null) values instead of #N/A?

WITH MEMBER \[Measures\].\[Unit Sales1\] AS 'iif(\[Unit Sales\] < -222222222,
   Null, \[Unit Sales\])'
SELECT \[Time\].\[Year\].Members ON Columns, \{\[Unit Sales1\]\} ON Rows
FROM Sales 

The answer: Check for small negative values. This formula is handy when you want to use the NON EMPTY clause to remove rows or columns that contain values that you don't have permission to view.