I have an ASP.Net that raise an exception that I cannot have the user to reproduce.

The exception I can trap (using the Global.asax Application_Error event) is:

Error Message: Object reference not set to an instance of an object.
Page Error Occurred: /ChecklistProcessList.aspx
ExceptionType: System.Exception
Stack Trace: at ISNet.WebUI.ISNetControl.ControlRequestHandler(Object Ԗ, EventArgs ԗ) at System.Web.UI.Control.OnPreRender(EventArgs e) at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

What can I do in order to get more details as none of the methods shown in the trace are mine?