GeckoFx: Accessing the Document Elements

When using the GeckoFx version 1.9.1.0 browser control. it is important to use the correct version of the XULRunner.
When I tried to access the Document Elements with the 1.9.1.0 version of the XULRunner with this code:

geckoBrowser.Document.GetElementById("_mainTableDiv");

this is the error I encountered:

“Unable to cast COM object of type 'System.__ComObject' to interface type 
'Skybound.Gecko.nsIDOMNSElement'. This operation failed because the 
QueryInterface call on the COM component for the interface with 
IID '{F0AEF489-18C5-4DE6-99D5-58B3758B098C}' failed due to the following 
error: No such interface supported (Exception from HRESULT: 0x80004002 
(E_NOINTERFACE)).”

It was fixed by using the 1.9.1.4 version of the XULRunner.
Hope this helps someone.