Get Saturday and Sunday date to send Birthday's greeting - vba

Question

Hi Guys I'm kind of new to the macros and how to set it up.
I'm trying to run a automatic birthday macros that send an email out to people saying a happy birthday message.
but I'm struggling with when its Monday i want it to initiate a message for the weekend birthdays as well, but only on a Monday. My Code keeps saying "Run-time error '13': type mismatch". Here is my Code please help as I've been struggling a week with it
Sub send_bday_greet2()
Dim i As Long
Dim vbSunday As String, vbSaturday As String
For i = 2 To Sheets("Sheet1").Range("a1048576").End(xlUp).Row
If Day(Now()) = Day(CDate(Sheets("Sheet1").Range("c" & i).Value)) And Month(Now()) = Month(CDate(Sheets("Sheet1").Range("c" & i).Value)) Then
Call sending_bday_greetings_method2(Sheets("Sheet1").Range("a" & i).Value, Sheets("Sheet1").Range("b" & i).Value)
ElseIf Day(Now(vbMonday)) = Day(CDate(Sheets("Sheet1").Range("c" & i).Value)) And Month(Now(vbSaturday)) And Month(Now(vbSunday)) = Month(CDate(Sheets("Sheet1").Range("c" & i).Value)) Then
Call sending_bday_greetings_method2(Sheets("Sheet1").Range("a" & i).Value, Sheets("Sheet1").Range("b" & i).Value)
End If
Next
End Sub
Sub sending_bday_greetings_method2(nm As String, emid As String)
Dim olApp As Outlook.Application
Dim olMail As MailItem
Set olApp = New Outlook.Application
Set olMail = olApp.CreateItem(olMailItem)
s = "<p> <p align='left'><font size='3' face='arial' color='blue'><i> Dear " & nm & ", </p>" & vbNewLine
s = s & "<p> <p align='CENTER'><font size='3' face='arial' color='red'><i> We Wish you a very Happy Birthday! </p>" & vbNewLine
s = s & "<left><p align='CENTER'><img src=""http://simplyizzy.files.wordpress.com/2012/05/happy_birthday1.png"">" & vbNewLine
s = s & vbNewLine & "<left><p><p align='Left'><font size='3' face='arial' color='blue'><i>Regards<br>" & "Reutech Radar Systems</p>"
With olMail
.To = emid
.Subject = "Happy B'day!"
.HTMLBody = s
.Send
End With
Set olApp = Nothing
Set olMail = Nothing
End Sub

Answer 1

Your 1st issue is with Dim vbSunday As String, vbSaturday As String.
vbSaturday and vbSaturday are constants in VBA that are numbers, and you're trying to use them as String.
Furthermore, they are most probably protected so you won't be able to use their names as variable's name.
Your second issue is with Now(vbMonday) and others, you'll need to use a function like this to get the last day from the current date :
Public Function GetLastDay(ByVal DayAsVbConstant As Integer) As Date
GetLastDay = Now - (Weekday(Now, DayAsVbConstant) - 1)
End Function
Here is a revision of your code :
Sub send_bday_greet2()
Dim i As Long
Dim wS As Worksheet
Dim SendMessage As Boolean
Dim BirthDay As Date
'Set wS = ThisWorkbook.Sheets("Sheet1")
Set wS = ThisWorkbook.Sheets("Feuil1")
With wS
For i = 2 To .Range("A" & .Rows.Count).End(xlUp).Row
SendMessage = False
BirthDay = CDate(.Range("C" & i).Value)
Select Case True
Case Day(Now()) = Day(BirthDay) And Month(Now()) = Month(BirthDay)
'Birthday this day
SendMessage = True
Case Weekday(Now) = vbMonday And ( _
Day(GetLastDay(vbSaturday)) = Day(BirthDay) And _
Month(GetLastDay(vbSaturday)) = Month(BirthDay))
'Birthday on Saturday
SendMessage = True
Case Weekday(Now) = vbMonday And ( _
Day(GetLastDay(vbSunday)) = Day(BirthDay) And _
Month(GetLastDay(vbSunday)) = Month(BirthDay))
'Birthday on Sunday
SendMessage = True
Case Else
End Select
If SendMessage Then Call sending_bday_greetings_method2(.Range("a" & i).Value, .Range("b" & i).Value)
Next i
End With 'wS
End Sub
And the part to send the mail :
Sub sending_bday_greetings_method2(ByVal nm As String, ByVal emid As String)
Dim olApp As Outlook.Application
Dim olMail As MailItem
Set olApp = New Outlook.Application
Set olMail = olApp.CreateItem(olMailItem)
s = "<p> <p align='left'><font size='3' face='arial' color='blue'><i> Dear " & nm & ", </p>" & vbNewLine
s = s & "<p> <p align='CENTER'><font size='3' face='arial' color='red'><i> We Wish you a very Happy Birthday! </p>" & vbNewLine
s = s & "<left><p align='CENTER'><img src=""http://simplyizzy.files.wordpress.com/2012/05/happy_birthday1.png"">" & vbNewLine
s = s & vbNewLine & "<left><p><p align='Left'><font size='3' face='arial' color='blue'><i>Regards<br>" & "Reutech Radar Systems</p>"
With olMail
.To = emid
.Subject = "Happy B'day!"
.HTMLBody = s
.Display
'.Send
End With
Set olApp = Nothing
Set olMail = Nothing
End Sub