I am getting an error at the line,
ShutdownDateTime = Nz(DLookup("shutdowndatetime", "servert"), #1/1/2100#)
it shows up in yellow.  What am i doing wrong?

here is the subroutine.

Details

Private Sub Form_Timer()

    Dim ShutdownDateTime As Date
    
    Me![CurrentTimeLbl].Caption = Format$(Now(), "dddd, mm/dd/yyyy  h:nn:ss AM/PM")
    
    'Status "Checking for shutdown" & Format(Now(), "hh:nn:ss")
    ShutdownDateTime = Nz(DLookup("shutdowndatetime", "servert"), #1/1/2100#)
    
    If ShutdownDateTime <= Now() Then
            'we may need to shut down, check when the database started
           If TempVars("startuptime") > ShutdownDateTime Then
                'the system started after the last forced shutdown, so we are ok
            Exit Sub
        Else
            'the system started before the shutdown was issued, we need to SHUT DOWN!
        Status "MUST SHUT DOWN!"
        
        DoCmd.OpenForm "ShutDownF"
        
        End If
        
        Else
            'we do not need to shut down, it is scheduled in the future
            
        End If
        
End Sub