Using the following function from...
http://www.cpearson.com/excel/colors.aspx

I [ALT] F11, right-click on Modules, Insert and pasted..

Function ColorIndexOfOneCell(Cell As Range, OfText As Boolean, _
DefaultColorIndex As Long) As Long
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''
' ColorIndexOfOneCell
' This returns the ColorIndex of the cell referenced by Cell.
' If Cell refers to more than one cell, only Cell(1,1) is
' tested. If OfText True, the ColorIndex of the Font property is
' returned. If OfText is False, the ColorIndex of the Interior
' property is returned. If DefaultColorIndex is = 0, this
' value is returned if the ColorIndex is either xlColorIndexNone
' or xlColorIndexAutomatic.
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''
Dim CI As Long

Application.Volatile True
If OfText = True Then
CI = Cell(1, 1).Font.ColorIndex
Else
CI = Cell(1, 1).Interior.ColorIndex
End If
If CI < 0 Then
If IsValidColorIndex(ColorIndex:=DefaultColorIndex) = True Then
CI = DefaultColorIndex
Else
CI = -1
End If
End If

ColorIndexOfOneCell = CI

End Function

....in A2, I put the formula =COLORINDEXOFONECELL(C1,FALSE,1)

Resulting error: Sub or Function not defined on line....
If IsValidColorIndex(ColorIndex:=DefaultColorIndex) = True Then
CI = DefaultColorIndex

....with IsValidColorIndex highlighted.

What's wrong?
thanks