AutoCAD Architect 2013 - "Object reference not set to an instance of an object"

I was in paper view adding the final touches to the title block (copy/paste text and a rectangle). I then saved the file and went to export it to a PDF and AutoCAD shut itself down.

I re-opened AutoCAD and opened the file from the recovery window and got the error "Object reference not set to an instance of an object." If I click 'Continue', the same error message keeps popping up.

I closed AutoCAD and rebooted my machine. I opened AutoCAD and tried to open the file that I saved just before AutoCAD crashed. I get the same error message. I am unable to get any further in AutoCAD because of this error message.

Is there any way to save this file or am I doomed to start over on this drawing?

Here's the Exception Text:

************* Exception Text **************

System.NullReferenceException: Object reference not set to an instance of an object.

at Autodesk.Aec.AecLayerManagerEx.standardFilter_Update(Object sender, UpdateUIEventArgs e)

at Autodesk.AutoCAD.LayerManager.MenuItem.UpdateItem(Boolean toolbarUpdate)

at Autodesk.AutoCAD.LayerManager.ToolBarButton.UpdateItem()

at Autodesk.AutoCAD.LayerManager.LayerManagerControl.Application_Idle(Object sender, EventArgs e)

at System.EventHandler.Invoke(Object sender, EventArgs e)

at Autodesk.AutoCAD.ApplicationServices.Core.Application.OnIdle()