MyGUI in Ogre3D not initialized @ get singleton

I am currently trying to display a message on an orge3D based application using MyGUI when a particular packet is received. In this case a message for displaying the download status of a file.

The problem is that @ line:

MyGUI::VectorWidgetPtr widPtr = MyGUI::LayoutManager::getInstance().loadLayout(layoutFileName);

the code crashes with an error.

0xC0000005: Access violation reading location 0x00000008

I can't seem to understand how to check and initialize the MyGUI::LayoutManager object as I can't seem to find any existing function.

OS in use: Windows 10