The code below will do what you want with some minor modifications.  In this
case, it is looping through a range of dates to determine whether it is a
work day.

Function CalcWorkDays(dtmStart As Date, dtmEnd As Date) As Integer

Dim intTotalDays As Integer ' Counter for number of days
Dim dtmToday As Date        ' To increment the date to compare

   On Error GoTo CalcWorkDays_Error

   intTotalDays = DateDiff("d", dtmStart, dtmEnd) + 1  'Start with total days
                                                       'Add one to include
First Day
   dtmToday = dtmStart                                 'Initiate compare date
   Do Until dtmToday > dtmEnd
       If Weekday(dtmToday, vbMonday) > 5 Then         'It is Saturday or
Sunday
           intTotalDays = intTotalDays - 1             'Take one day away
for Weekend day
       ElseIf Not IsNull(DLookup("[Holdate]", "Holidays", _
               "[Holdate] = #" & dtmToday & "#")) Then 'It is a holiday
           intTotalDays = intTotalDays - 1             'Take one day away
for the Holiday
       End If
   dtmToday = DateAdd("d", 1, dtmToday)                'Add a day for next
compare
   Loop    'Until dtmToday > dtmEnd                     All days have been
compared
   CalcWorkDays = intTotalDays                         'Return the value

CalcWorkDays_Exit:

   On Error Resume Next
   Exit Function

CalcWorkDays_Error:

   MsgBox "Error " & Err.Number & " (" & Err.Description & _
       ") in procedure CalcWorkDays of Module modDateFunctions"
   GoTo CalcWorkDays_Exit
End Function