Pete For a moment I thought it were different variable because i was using
shared methods and a shared field but i changed that and instanciated the
class to be sure that it is the same variable i'm using but that didn't solve
the problem.
Then I tried to put the data getting from my get-method in a session
variable. When i call my put(save) method i cast the session variable to the
wright type but at the point of entering my method i loose all data. The
casting etc. works fine.

Here's some of the code.
It's a web-application that calls data from a database over a business layer.

WebPage-code:

Private Sub commissionToPay(ByVal calculationDate As Date)
    Try
        Dim result As DataTable
        Dim isSaved As Boolean
        If Session("Commission") Is Nothing Then
            Session("Commission") = BL.getCommissionToPay(calculationDate, isSaved)
        End If
        If Not Session("Commission") Is Nothing AndAlso
Session("Commission").containskey(calculationDate) Then
            If Session("Commission").ContainsKey("CommissionsToPay") Then
                result = CType(Session("Commission")("CommissionsToPay"),
DataSet).Tables(0)
                result.DefaultView.Sort = "EmployeeName"
                dtgAll.DataSource = result.DefaultView
                    dtgAll.DataBind()
                pnlAll.Visible = True
                btnAcceptToPay.Visible = Not isSaved
                btnExport.Visible = False
                lblHdAllEmployeeID.Visible = True
            End If
        Else
            lblError.Text = rStrings.GetString("NoResults")
        End If
    Catch ex As Exception
        lblError.Text = ex.Message
        lblError.Visible = True
        pnlMsg.Visible = True
    End Try
End Sub

Private Sub btnAcceptToPay_Click(ByVal sender As Object, ByVal e As
System.EventArgs) Handles btnAcceptToPay.Click
  'Save commission and orders for faster generation of reports.
   Try
    Dim ht As Hashtable
    ht = CType(Session("Commission"), Hashtable)
    If BL.saveAcceptCommissionToPay(ht) Then
        btnAcceptToPay.Visible = False
    End If
   Catch ex As Exception
    lblError.Text = ex.Message
    lblError.Visible = True
    pnlMsg.Visible = True
   End Try
End Sub

BL-code(partial)

Public Shared Function getCommissionToPay(ByVal calculationdate As Date,
ByRef isSaved As Boolean) As Hashtable
  Dim result As DataSet
  Dim htCommissions As Hashtable

  Try
  'First check if commission not saved yet.
       result = DAL.Commission.getCommissionToPayOnDate(calculationdate)
       If Not result Is Nothing Then
    isSaved = True
    htCommissions.Add("CommissionsToPay", result)
    Return htCommissions
        Else
    isSaved = False
    result = New DataSet
    'check if result in cache
    If _htCommissions Is Nothing OrElse _CalculatedFor <> calculationdate Then
        htCommissions = getCommission(calculationdate)
    Else
        htCommissions = _htCommissions
    End If
   Catch ex As Exception
    Throw
   End Try
End Function

Public Shared Function saveAcceptCommissionToPay(ByVal ht As Hashtable) As
Boolean '(ByVal commissionData As Hashtable) As Boolean
    Dim succesfull As Boolean = False
    Dim CommissionToPay As DataSet
    Dim commission As dsCommissions
    Dim pcID, pcOrderID As Int64
    Dim target As dsCommissions.TargetsRow
    Dim realised As dsCommissions.SalesCountersRow
    Dim corr As dsCommissions.OrderCorrectionRow
    'Dim  = _htCommissions

    'Table0 = totals of commission and corrections
    'table1 = total of corrections for 1 month
    'Table2 = periods to print report
    Try
        'save totals & corrections
        If Not ht Is Nothing Then
            If ht.ContainsKey("CommissionToPay") Then
                CommissionToPay = ht("CommissionToPay")
   
when i get in this method then the parameter ht display the value
{length=error: cannot obtain value) where at the point of casting it sais
{length=2}

dear guys,

I've found a work around.
I created a new function with the same parametere. In that function the
hashtable is filled with the values. I copied the code from the previous
function except of the iteration of the for next loop. this is were i call
again the previous function but instead i pass a dataset to that function.
This way it works fine. Thank you all.

Peter,
I'll keep your suggestions in mind. this was my first post and i didn't
exactly know what to post. thanks again.