Unexpected #Value! in excel when filtered for members

Hi All

I am using this measure in my cube. I have two hierarchies for date dimension. One hierarchy always fails when I filter for members. In this case if I am filtering for week, Year level fails. Please suggest a solution.

 iif(
([Calendar].[DATE].currentmember.level.name = "YEAR") OR

 ([Calendar].[DATE].currentmember.level.name = "QUARTER") OR

 ([Calendar].[DATE].currentmember.level.name = "MONTH") OR

([Calendar].[DATE].currentmember.level.name = "DATE"),

 
(
IIF((([Measures].[Yeild], [Calendar].[DATE].CurrentMember)-

([Measures].[Yeild], [Calendar].[DATE].PrevMember))>0,

 (([Measures].[Yeild], [Calendar].[DATE].CurrentMember)-
([Measures].[Yeild], [Calendar].[DATE].PrevMember))/100,0)),

iif(([Calendar].[Week].currentmember.level.name = "YEAR NBR")
or
([Calendar].[Week].currentmember.level.name = "WEEK NBR")
or
([Calendar].[Week].currentmember.level.name ="DATE DAY"),

 
(IIF((([Measures].[Yeild],[Calendar].[Week].CurrentMember)-

([Measures].[Yeild], [Calendar].[Week].PrevMember))>0,

 (([Measures].[Yeild], [Calendar].[Week].CurrentMember)-

([Measures].[Yeild], [Calendar].[Week].PrevMember))/100,0)),

 ([Measures].[Yeild])))

Thanks in Advance

Veena