I've rebuilt the module using ReportViewer v14 (previously using v11 on pre DNN v9).
Updated the project references and any references in files from v11 to v14.
Placed v14 Webforms dll in the bin folder of the application and installed the _Install.zip.
Outside of edit mode the pages that use the report viewer are no longer visible to any IE v8 or older browsers (or compatible alternatives) but are appearing correctly on IE v9 of newer (again or compatible alternatives) which is to be expected as the older browsers are no longer supported by report viewer.
I've gone into the pages and tried to edit again but have unfortunately been met with the same error so it would appear that it isn't the ReportViewer version:
Server Error in '/' Application.
Cannot unregister UpdatePanel with ID 'DocMap' since it was not registered with the ScriptManager. This might occur if the UpdatePanel was removed from the control tree and later added again, which is not supported.
Parameter name: updatePanel
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentException: Cannot unregister UpdatePanel with ID 'DocMap' since it was not registered with the ScriptManager. This might occur if the UpdatePanel was removed from the control tree and later added again, which is not supported.
Parameter name: updatePanel
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[ArgumentException: Cannot unregister UpdatePanel with ID 'DocMap' since it was not registered with the ScriptManager. This might occur if the UpdatePanel was removed from the control tree and later added again, which is not supported.
Parameter name: updatePanel]
System.Web.UI.PageRequestManager.UnregisterUpdatePanel(UpdatePanel updatePanel) +222
System.Web.UI.UpdatePanel.OnUnload(EventArgs e) +121
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +141
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Control.UnloadRecursive(Boolean dispose) +355
System.Web.UI.Page.UnloadRecursive(Boolean dispose) +24
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +12361809
System.Web.UI.Page.ProcessRequest() +119
System.Web.UI.Page.ProcessRequest(HttpContext context) +99
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +913
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +165
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.36415