For starters, your ground plane is still in the way.
It should be set at shadow catch only (if you need shadows).
Otherwise toggle ground plane completely OFF.

Only then will you be able to set your scene and see where the background inmage is exactly.
It works here.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!