I've been receiving server errors with a .Net 3.5 ASP app using Ultra Chart. The load test was performed using CapCal (I have details on this tool and confidence in its results) simulating 20 users over a 3 minute period. I've included the server log error below.  Any help from Infragistics would be welcome. 

Server Log

Event Type: Warning
Event Source: ASP.NET 2.0.50727.0
Event Category: Web Event
Event ID: 1309
Date:  2/13/2009
Time:  4:44:48 PM
User:  N/A
Computer: TESTTOOLSERVER
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 2/13/2009 4:44:48 PM
Event time (UTC): 2/13/2009 9:44:48 PM
Event ID: 1eea0fc7138a4405b4161b8e99ac7b38
Event sequence: 21137
Event occurrence: 548
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/1/Root/CTEForesight-1-128790067159531250
    Trust level: Full
    Application Virtual Path: /CTEForesight
    Application Path: C:\Inetpub\wwwroot\CTEForesight\
    Machine name: TESTTOOLSERVER
 
Process information:
    Process ID: 4968
    Process name: w3wp.exe
    Account name: NT AUTHORITY\NETWORK SERVICE
 
Exception information:
    Exception type: NullReferenceException
    Exception message: Object reference not set to an instance of an object.
 
Request information:
    Request URL: "removed for security reasons"

    Request path: /CTEForesight/Tests.aspx
    User host address: 10.1.10.115
    User: 
    Is authenticated: False
    Authentication Type: 
    Thread account name: NT AUTHORITY\NETWORK SERVICE
 
Thread information:
    Thread ID: 13
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: False
    Stack trace:    at Infragistics.WebUI.UltraWebChart.UltraChart.Infragistics.UltraChart.Resources.IChartComponent.Invalidate(CacheLevel cacheLevel)
   at Infragistics.UltraChart.Resources.Appearance.AppearanceHelper.UpdateParentProperty()
   at Infragistics.UltraChart.Resources.Appearance.PaintElement.set_StrokeWidth(Int32 value)
   at Infragistics.UltraChart.Resources.Appearance.HistogramLineAppearance..ctor(IChartComponent component)
   at Infragistics.UltraChart.Resources.Appearance.HistogramChartAppearance..ctor(IChartComponent component)
   at Infragistics.WebUI.UltraWebChart.UltraChart.CreateAppearanceObjects()
   at Infragistics.WebUI.UltraWebChart.UltraChart.CreateChart()
   at Infragistics.WebUI.UltraWebChart.UltraChart..ctor()
   at ASP.tests_aspx.__BuildControlchtTrends()
   at ASP.tests_aspx.__BuildControlContent2(Control __ctrl)
   at System.Web.UI.CompiledTemplateBuilder.InstantiateIn(Control container)
   at ASP.masterpages_masterpage_master.__BuildControlcpMainContent()
   at ASP.masterpages_masterpage_master.__BuildControlform1()
   at ASP.masterpages_masterpage_master.__BuildControlTree(masterpages_masterpage_master __ctrl)
   at ASP.masterpages_masterpage_master.FrameworkInitialize()
   at System.Web.UI.UserControl.InitializeAsUserControlInternal()
   at System.Web.UI.MasterPage.CreateMaster(TemplateControl owner, HttpContext context, VirtualPath masterPageFile, IDictionary contentTemplateCollection)
   at System.Web.UI.Page.get_Master()
   at System.Web.UI.Page.ApplyMasterPage()
   at System.Web.UI.Page.PerformPreInit()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)