teeChart: Catastrophic failure

i don't want to display the tChart.
all i need to do is create an image file using tChart.
when i run the application a get this error:

"System.Runtime.InteropServices.COMException: Catastrophic failure"

this web application is on a server and the tCharts are formated using the aspx.vb code behind pages.

Dim MyTable As New Data.DataTable("MyTable")
Dim ColValue As New Data.DataColumn("Value", Type.GetType("System.Int32"))
Dim ColDateTime As New Data.DataColumn("DateTime", Type.GetType("System.DateTime"))
MyTable.Columns.Add(ColValue)
MyTable.Columns.Add(ColDateTime)
Dim myChartRow As DataRow
Dim myChartAddRow As DataRow

For Each myChartRow In dstChartInfo.Tables("ChartInfo").Rows
myChartAddRow = MyTable.NewRow()
myChartAddRow("Value") = myChartRow("Value")
myChartAddRow("DateTime") = myChartRow("DateTime")
MyTable.Rows.Add(myChartAddRow)
Next

Dim FirstView As New Data.DataView(MyTable)
Dim tChart1 As New TChart()
tChart1.AddSeries(ESeriesClass.scLine)

With tChart1.Series(0)
.YValues.ValueSource = "Value"
.XValues.ValueSource = "DateTime"
.XValues.DateTime = True
.DataSource = FirstView
.CheckDataSource()
.VerticalAxis = EVerticalAxis.aLeftAxis
.Color = Convert.ToUInt32(System.Drawing.Color.Blue)
End With

With tChart1.Axis.Bottom
.Labels.DateTimeFormat = "dd/MM/yyyy HH:mm:ss"
.Labels.Multiline = True
.MinorTickLength = 2
.MinorTicks.Visible = True
.MinorTickCount = 4
.TickLength = 8
.Ticks.Visible = True
End With

With tChart1.Axis.Left
.GridPen.Color = Convert.ToUInt32(System.Drawing.Color.LightGray)
.GridCentered = True
.MinorTickLength = 2
.MinorTicks.Visible = True
.TickLength = 8
.Ticks.Visible = True
End With

With tChart1.Axis.Right
.GridPen.Color = Convert.ToUInt32(System.Drawing.Color.White)
.MinorTickLength = 2
.MinorTicks.Visible = True
.TickLength = 8
.Ticks.Visible = True
End With

With tChart1.Header
.Visible = False
End With

With tChart1
.Panel.Color = Convert.ToUInt32(System.Drawing.Color.White)
.Legend.Visible = False
.Aspect.View3D = False
.Panel.BevelOuter = EPanelBevel.bvNone
End With

'File.Delete(Server.MapPath((Session("username")) & ".jpeg"))
If IsItView = 1 Then
With tChart1.Export.asJPEG
.Height = 250
.Width = 570
End With
Else
With tChart1.Export.asJPEG
.Height = 448
.Width = 1012
End With
End If

With tChart1.Export
.asJPEG.CompressionQuality = 90
.asJPEG.GrayScale = False
.asJPEG.SaveToFile(Server.MapPath((Session("username")) & ".jpeg"))
End With

please help me.
thanks,
tom