We are using ultrawebchart session based deployment ,exactly as given in example .

<igchart:ultrachart id="UltraChartAssetSummary" runat="server" Width="500px" Height="200px" ChartType="PieChart3D"
            Version="6.2" Section508Compliant="False" CrossHairColor="Blue" EnableCrossHair="False" ChartImagesPath="ChartImages"
            ImagePipePageName="ImagePipe.Aspx" EnableScrollBar="False" EmptyChartText="Data Not Available. Please call UltraChart.Data.DataBind() after setting valid Data.DataSource"
            BackColor="#f7f7ef" Transform3D-Perspective="50" Transform3D-ZRotation="0" Transform3D-Scale="65" Transform3D-XRotation="-310"
            Transform3D-YRotation="80" BackgroundImageStyle="StretchedFit" Visible="False">
            <Border Thickness="0"></Border>
            <PieChart3D ConcentricSpacing="0.25" BreakAlternatingSlices="False" OthersCategoryPercent="0"
             BreakOthersSlice="False" BreakDistancePercentage="10" StartAngle="80" ColumnIndex="-1" PieThickness="20"
             BreakAllSlices="False" RadiusFactor="1000" ShowConcentricLegend="True">
             <Labels Font="Microsoft Sans Serif, 7.8pt" Visible="True" FormatString="&lt;PERCENT_VALUE:#0.00&gt;%"
              LeaderLineThickness="1" FillColor="Transparent" LeaderLinesVisible="True" BorderDrawStyle="Solid"
              Format="Custom" BorderThickness="0" LeaderEndStyle="ArrowAnchor" FontColor="Black" BorderColor="Black"
              LeaderDrawStyle="Dot"></Labels>
            </PieChart3D>
            <ClientSideEvents ClientOnMouseClick="UltraChartAssetSummary_ClientOnMouseClick"></ClientSideEvents>
            <Data>
             <EmptyStyle>
              <PointPE FillOpacity="255" Fill="Transparent"></PointPE>
              <PE FillOpacity="255" Fill="Transparent"></PE>
             </EmptyStyle>
            </Data>
            <TitleLeft Visible="False" Orientation="VerticalLeftFacing" HorizontalAlign="Near" Extent="26"
             Location="Left">
             <Margins Bottom="5" Top="5" Right="5" Left="5"></Margins>
            </TitleLeft>
            <ColorModel ModelStyle="CustomLinear" AlphaLevel="255"></ColorModel>
            <Legend Font="Arial, 8pt" Visible="True" BorderThickness="0" SpanPercentage="40" BackgroundColor="Transparent"
             FormatString="&lt;ITEM_LABEL&gt;">
             <Margins Bottom="5" Top="5" Right="5" Left="5"></Margins>
            </Legend>
            <Axis>
---so on
</gchart:ultrachart>

We are having issue in server that sometimes we are getting Access Denied error and sometimes it works fine .It's a urgent issue .Please me know if we are missing something.