Handle Null values in calculated measure and excel

Hi Experts,

I am always getting the (null) value while browsing the cube for the dimesnion packtype value (Hanging Sacks) , I am unsure why I am getting a null value and hence I am getting the #value error in Excel.  So the user is unable to see any data i report. Please correct my MDX below and  resolve this issue.

Here is the MDX used for the calculated measure.

sum(
{[Pack Type].[Pack Type].&[Hanging Sack]},[Measures].[Totes]
       )
 
Thanks,

Sreekanth.