ASP.NET - can't insert data and hours in database (dataset) - asp.net

Question

I'm creating an application where people can insert an event with information such as eventname, location, date, hours, ...
There are 3 steps. the first 2 steps with the inserts were succesfully inserted. But at step 3 where they have to insert a startDay (Startdag), endDay(Einddag), starthour(startUurt), endHour(eindUur) I can't get it fixed.
In the presentationlayer I'm using the calendarExtender for Startday and Endday with format d MMMM yyyy with and target txt_sDag and txt_eDag
In dataset "DAL_Planit3.xsd" I've given endDay and startDay as type "datetime" and startHour and endHour as type String (becoz we will only read it, we won't be doing anything with it).
Can someone please help me?
StepThree.aspx.vb
Protected Sub btn_next_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_next.Click
Try
Dim BLLdata As New BLL_Data
Dim eventID As Integer = Session.Item("eventID")
Dim plaatsID As Integer = Session.Item("plaatsID")
Dim data As New CL_Data
data.Einddag = txt_eDag.Text
data.Startdag = CDate(txt_sDag.Text)
data.Einddag = CDate(txt_eDag.Text)
data.Einduur = txt_eUur.Text
data.StartUur = txt_sUur.Text
data.FKEvenementId = eventID
data.FKPlaatsId = plaatsID
BLLdata.insertData(data)
lbl_feedback.Text = "Data succesful inserted!"
Catch ex As Exception
lbl_feedback.Text = "Data not inserted! " + ex.Message
End Try
End Sub
End Class
*BLL_Data.vb*
' INSERT DATA
Public Function insertData(ByVal data As CL_Data) As String
Dim feedback As String = Nothing
Try
adapterDatum3.Insert(data.Startdag, data.Einddag, data.StartUur, data.Einduur, data.FKPlaatsId, data.FKEvenementId)
'adapterDatum.Insert(data.Startdag, data.Einddag, data.StartUur, data.Einduur, data.FKPlaatsId, data.FKEvenementId)
feedback = "Data is toegevoegd"
Catch ex As Exception
feedback = ex.Message
End Try
Return feedback
End Function
CL_Data
Public Class CL_Data
Private iDataId As Integer
Public Property DataID() As Integer
Get
Return iDataId
End Get
Set(ByVal value As Integer)
iDataId = value
End Set
End Property
Private dStartDag As Date
Public Property Startdag() As Date
Get
Return dStartDag
End Get
Set(ByVal value As Date)
dStartDag = value
End Set
End Property
Private dEindDag As Date
Public Property Einddag() As Date
Get
Return dEindDag
End Get
Set(ByVal value As Date)
dEindDag = value
End Set
End Property
Private tStartUur As String
Public Property StartUur() As String
Get
Return tStartUur
End Get
Set(ByVal value As String)
tStartUur = value
End Set
End Property
Private tEindUur As String
Public Property Einduur() As String
Get
Return tEindUur
End Get
Set(ByVal value As String)
tEindUur = value
End Set
End Property
Private iFKPlaatsId As Integer
Public Property FKPlaatsId() As Integer
Get
Return iFKPlaatsId
End Get
Set(ByVal value As Integer)
iFKPlaatsId = value
End Set
End Property
Private iFKEvenementId As Integer
Public Property FKEvenementId() As Integer
Get
Return iFKEvenementId
End Get
Set(ByVal value As Integer)
iFKEvenementId = value
End Set
End Property
End Class