Using a Dimension/ Measure in a Where clause of Another Dimension/ Measure in IDT

Hi All

I am building a Universe using the Information Design Tool. In the Business Layer, I need to use a created Business Layer Dimension (not Table) in a Where clause of another Dimension as follow:

Dimension: "Current Week No"

     SELECT:

          budgets.dbo.Calenderweeks.WeekNo

     WHERE:

          budgets.dbo.Calenderweeks.EndDate = convert(SMALLDATETIME, {fn CURDATE()})

Dimension: "Last Week No"

     SELECT:

          budgets.dbo.Calenderweeks.WeekNo

     WHERE:

          budgets.dbo.Calenderweeks.WeekNo = @Select(Dimensions\Current Week No) -1

The First Dimension is working well. However, the "Last Week No" shows NOTHING (I.e. I do not get the any results from)

Anyone can explain why I am not getting results from the second Dimension and how I can use a Dimension/ Measure in a where clause of another Dimension/ Measure ?