I have a workbook that has a reference to an add-in. I know that the
reference works, because I can call the addin's functions and variables from
within my workbook.

However, in my addin, I refer to the workbook's worksheets using their
codenames (so that if my users change the worksheet name, it doesn't mess up
my code). When I run the code, I get an error message:

"Object doesn't support this property or method"

Here's an example --

ActiveWorkbook has a worksheet with the codename shtDiary

Addin code looks like this:

strDiaryDate = ActiveWorkbook.shtDiary.Cells(1,1).Value2

if I change it to refer to the collection using the worksheet name it works
just fine:

strDiaryDate = ActiveWorkbook.Worksheets("Diary").Cells(1, 1).Value2

Why isn't this working? Any help greatly appreciated.

Dianne