spot errors in VB

Please spot the errors in the following code in VB.NET:

Dim Diff As String = con.ExecuteCommand(“SELECT DATEDIFF(Day, (select [date] from table where Username = ‘” + txtUserName.Text + “‘), ‘” & DateTime.Now.ToString() & “‘)”)
If (Diff > 30) Then
Response.Redirect(“PleaseChangeMyPassword.aspx”)
End If

 

( find at least 3…)

Side note:

No wonder Visual Basic has died ( more or less). Guess future of server javascript ….