On reviewing your callstack, it's the ErrorController within your application which is throwing the error.
I would guess it's trying to e-mail you the error details, rather than throwing the exception.
This obviously needs to be fixed, but to see your error now try adding this into your application.ini
resources.frontController.params.displayExceptions = 1
phpSettings.display_startup_errors = 1
phpSettings.display_errors = 1
phpSettings.error_reporting = "8191"
resources.frontController.throwExceptions = true
This will throw any errors to screen, rather than trying to handle them.