Is there anything wrong with this function? Whenever I call it, I get an error saying "Wrong number of arguments or invalid property assignment" with the Day function highlighted...

Code:
Private Function DaysInMonth(iMonth As Long, iYear As Long) As Integer

    DaysInMonth = Day(DateSerial(iYear, iMonth + 1, 0))

End Function
... it looks okay to me. This is code running under VBA in MS Access if that makes a difference.