I'm trying to use the complex math functions (e.g., Complex(), ImSum,
ImProduct(), etc.) in VBA. However, I encounter the error message "Sub or
Function not defined."

In earlier verions of Excel (2000, 2003), I reference the Analysis ToolPak -
VBA (atpvbaen.xla) in the macro module and macro works correctly.

However, in Excel 2007 when I do the same thing I encounter the problem
described before. I specify Tool Reference and click on atpvbaen.xls
entry. This code causes the problem
Sub mysub()
[a1] = Complex(1, 2)
End Sub

The error message "Sub or Function not defined." appears and the debugger
highlights the text "Complex".

Any suggestions will be appreciated. In particular, whatever code is
suggested needs to work in earlier versions of Excel.

TIA

Jim T