Converting to datetimes (causing Arithmetic overflow error converting expression to data type datetime)

Here is a slimmed down version of my codebehind:
Imports System.Web.Configuration Imports System.Data.SqlClient Partial Class AVForm2_Default2 Inherits System.Web.UI.Page Protected Sub Submit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Submit.Click 'database connection Dim connstring As String = WebConfigurationManager.ConnectionStrings("ConnectionString").ToString() Dim connection As SqlConnection = New SqlConnection(connstring) Dim command As New SqlCommand Dim sqlstring As New StringBuilder sqlstring.Append("INSERT INTO RequestEquipment ( ") sqlstring.Append("[committee], ") sqlstring.Append("[venue], ") sqlstring.Append("[campus], ") sqlstring.Append("[department], ") sqlstring.Append("[contactname], ") sqlstring.Append("< ...