String was not recognized as a valid DateTime error with tt

[lleemon]

Anyone know why I get an error when my time is PM? The MSDN doc says tt works with AM/PM.

Error I get is: String was not recognized as a valid DateTime

sDeadlineDtTm = "9/3/2011 1:30PM"

            Try
                dtDeadlineDtTm = DateTime.ParseExact(sDeadlineDtTm, "M/d/yyyy H:mmtt", System.Globalization.CultureInfo.CreateSpecificCulture("en-US"))
            Catch ex As Exception
                Dim csType As Type = Me.GetType()
                Dim sOutput As String = ex.ToString
                ClientScript.RegisterStartupScript(csType, "startup", "<script>alert('Response Deadline error.');</script>")

                Exit Sub
            End Try

Thanks in advance.