Range.Validation Add Fails with 1004 error

[Hila]

Hi,

I have a strange problem with my Excel Macro.
I am using the following code in the Worksheet Change event routine:

        Category = "=EmptyList"
        With Worksheets(5).Cells(9, 3).Validation
            .Delete
            .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
            xlBetween, Formula1:=Category
            .IgnoreBlank = True
            .InCellDropdown = True
            .InputTitle = ""
            .ErrorTitle = ""
            .InputMessage = ""
            .ErrorMessage = ""
            .ShowInput = True
            .ShowError = True
        End With

The purpose of this code is to assign a data validation of type list to a cell.

The code is working just fine when it is activated from the Worksheet Change event routine. However, when I am copying this exact code to a regular routine (that is part of a Module) - I get the following error:

Run time error 1004: Application-defined or object-defined error.

What do I do wrong???!!!!

Please help!

p.s. I am using Excel 2007