Custom error pages in Reporting Services 2008

Answer 1

Unfortunately, you can't when using the visual aspects of SSRS. You can if you consume the reports directly via SOAP and the web service.

Answer 2

I had a similar problem and came up with the following solution. It's prone to breaking things if Microsoft changes this particular method. The following code would be added to the header of the page to make sure it runs after the ReportViewer javascript is loaded, but before an instance of the RSClientController is created.

// This replaces a method in the ReportViewer javascript. If Microsoft updates 
// this particular method, it may cause problems, but that is unlikely to 
// happen.The purpose of this is to redirect the user to the error page when 
// an error occurs. The ReportViewer.ReportError event is not (always?) raised 
// for Remote Async reports
function OnReportFrameLoaded() {
    this.m_reportLoaded = true;
    this.ShowWaitFrame(false);

    if (this.IsAsync)
    {
        if(this.m_reportObject == null)
        {
            window.location = 
                '<%= HttpRuntime.AppDomainAppVirtualPath %>/Error.aspx';
        }
        else
        {
            this.m_reportObject.OnFrameVisible();
        }
    }
}
RSClientController.prototype.OnReportFrameLoaded = OnReportFrameLoaded;

The original code from the Microsoft ReportViewer script file (inside the Microsoft.ReportViewer.WebForms, 8.0.0.0, .Net Framework 3.5 SP1) is:

function OnReportFrameLoaded()
{
    this.m_reportLoaded = true;
    this.ShowWaitFrame(false);

    if (this.IsAsync && this.m_reportObject != null)
        this.m_reportObject.OnFrameVisible();
}
RSClientController.prototype.OnReportFrameLoaded = OnReportFrameLoaded;