QRY returning error if value is blank?

Hi,

I am running the below expression to compare the diffence of 2 dates. If both dates are in the cell I would like it to return a 0 but if Date2 is blank I would like the difference to show. Right now I just get #ERROR if there is no date in date2. Any ideas would be greatly appreciated.

expr2: NetWorkDays([Date1],[Date2])

Option Compare Database

Public Function NetWorkdays(dteStart As Date, dteEnd As Date) As Integer

Dim intGrossDays As Integer
Dim dteCurrDate As Date
Dim i As Integer

intGrossDays = DateDiff("d", dteStart, dteEnd)
NetWorkdays = 0

For i = 0 To intGrossDays
dteCurrDate = dteStart + i
If Weekday(dteCurrDate, vbMonday) < 6 Then
End If
Next i

End Function